Séminaires de physique corpusculaire
Les séminaires du DPNC ont généralement lieu les
mercredis à 11h15
Semestre d'Automne 2007 - Semestre de Printemps 2008 - Semestre d'Automne 2008 - Semestre de Printemps 2009 - Semestre d'Automne 2009 - Semestre de Printemps 2010 - Semestre d'Automne 2010 - Semestre de Printemps 2011 - Semestre d'Automne 2011- Semestre de printemps 2012
Semestre de Printemps 2012
|Date||Conférencier||Titre du séminaire et Annonce|
|17 Feb. 2012||Dr Carla Aramo, INFN, Sezione di Napoli||New frontiers on photodetection|
|07 Mar. 2012
||Dr Giulio Saracino, University of Naples, Federico II||Silicon photomultiplier: features and applications|
|07 Mar. 2012
Knoting, Max Plank Institute
Candidat à un poste de doctorant
|Light emission in PMT and SiPM|
|14 Mar. 2012||Dr Chiara Casella, ETH Zurich||The AX-PET experiment: A demonstrator for an axial Positron Emission Tomography|
|28 Mar. 2012||Prof. Pasquale Blasi INAF, Arcetri Observatory, Firenze||Particle Acceleration in supernova remnants and its implications for the origin of galactic cosmic rays|
|18 Apr. 2012||Dr Simona Toscano, University of Wisconsin, Madison||Observation of Anisotropy in the arrival direction distribution of Cosmic Rays above TeV energies with IceCube|
|25 Apr. 2012||Prof. Norbert Wermes, University of Bonn||Pixel Detectors - trends and options for the future|
|09 May 2012
||Dr Philippe Mermod, University of Geneva||The Search for the Magnetic Monopole|
|09 May 2012
||Dr Carsten Rott, Center for Cosmology and Astroparticle Physics (CCAPP), Ohio University||The Search for Dark Matter with Neutrinos|
|3 Séminaires - Candidats - Postdoc ATLAS||Annonces et détails|
|20 Jun. 2012
||Dr Monica D'Onofrio, University of Liverpool||Searches for SUSY at the LHC: status and prospects|
Dr Carla Aramo, INFN, Sezioine di Napoli - New frontiers on photodetection
In the last years the use of new materials and new technologies opened the door to new kind of devices based on the coupling of well known properties of silicon with properties of other materials. In particular carbon material, in the form of carbon nanotubes, has been used to create heterojunction with interesting photoconductivity characteristics. The new photodetectors obtained show to have peculiar and interesting characteristics with quantum efficiency ranging from >35% to >15% in the investigated wavelength interval from near infrared to near ultraviolet region. The device characteristics, the silicon-carbon nanotubes heterojunction and some future improvements towards single photon detection, medical imaging and nano-opto-electronics will be briefly illustrated. access to the talk
Dr Giulio Saracino, University of Naples, Federico II - Silicon photomultiplier: features and applications
Silicon photomultipliers have been developed about ten years
ago and their use, alternative to traditional photomultiplier tubes, is increasing
more. They are an evolution of the avalanche photodiode working in Geiger mode
regime. Hundreds of such diodes are connected in parallel, allowing single
photon response, high detection efficiency, high gain at low bias voltage and
very good timing performance. In spite of their Geiger regime, they can be
considered linear devices, until the number of photons impinging is smaller
than the number of cells. Main drawbacks are high dark rate and temperature
dependence of some parameters.
The large success they are finding is confirmed by the multiplication of firms that are now producing such devices and the many typology of SiPM available.
In this talk I will discuss the main properties of silicon photomultiplier. A short description of the devices available on the market and to front-end electronics will be given too. A selected number of applications, in the particle physics context and not only, will be shown. access to the talk
Mac Knoting - Candidat à un poste de doctorant - Light emission in PMT and SiPM
Photomultiplier (PMT) are the standard light detector for applications with low levels of light and fast timing. This makes them ideal detectors in astroparticle physics. But the development in silicon photomultiplier (SiPM) technology is fast. They could, one day, replace the old PMTs. Both detectors show light emission under regular operation. This contributes to their noise and degrades the detector performance. I will present new studies on the light emission in Si avalanches, optical cross-talk imaging in SiPM and on the light emission responsible for the fast after-pulsing effect in PMTs.
Dr Chiara Casella, ETH, Zurich - The AX-PET experiment: A demonstrator for an axial Positron Emission Tomography
PET (Positron Emission Tomography) is a tool for in-vivo functional imaging,
successfully used since the earliest days of nuclear medicine. It is based
on the detection of the two coincident 511 keV photons from the annihilation
of a positron, emitted from a radiotracer injected into the body. Tomographic
analysis of the coincidence data allows for a 3D reconstructed image of the
The AX-PET experiment proposes a novel geometrical approach for a PET scanner, in which long scintillator crystals (LYSO) are placed axially in the tomograph, and are individually readout by G-APD’s, Geiger- mode Avalanche Photo Diodes, also known as Silicon Photomultipliers. Arrays of WLS strips, also individually readout by G-APD’s, are placed behind each layer of crystals, to measure the axial coordinate of the photon interaction point.
Two AX-PET modules have been built at CERN, and fully characterized with point-like Na-22 sources, demonstrating competitive performance in term of spatial and energy resolutions (respectively: R_FWHM ~ 1.35 mm in the axial direction; (ΔE/E)_FWHM ~ 12% at 511 keV). Used in coincidence, the two modules represent the demonstrator for a PET prototype. The demonstrator has been used for the reconstruction of images of several phantoms filled with F-18 based radiotracers. The AX- PET detector, its performance and the reconstructed images of different phantoms will be shown.
Since recently, digital Silicon Photomultipliers (dSiPM) from Philips are being investigated as alternative photodetectors for the AX-PET. With their highly integrated readout electronics and excellent intrinsic time resolution, dSiPM’s may allow for compact detector modules with Time of Flight capability (TOF-PET). Results about the first tests with dSiPM will also be reported. access to the talk
Prof. Pasquale Blasi, INAF, Arcetri Observatory, Firenze - Particle Acceleration in supernova remnants and its implications for the origin of galactic cosmic rays
The process of cosmic ray energization in supernova remnant shocks is described by the theory of non linear diffusive shock acceleration (NLDSA). Such theory is able to describe the acceleration itself, the dynamical reaction of accelerated particles on the shock, and the crucial phenomenon of the magnetic field amplification, the very key to generate high energy cosmic rays. I will illustrate the basic aspects of this theoretical framework, as well as its successes and problems. I will then discuss the observations, in X-rays and with Fermi-LAT and Cherenkov telescopes in the gamma rays that can provide tests of the so-called supernova remnant paradigm for the origin of cosmic rays. The implications of NLDSA for observations of cosmic ray spectra, composition and anisotropy will also be discussed. Finally, I will illustrate some new ideas on particle acceleration in partially ionized media that hold to promise to provide an unprecedented way to look at the sources of cosmic rays. access to the talk
Dr Simona Toscano, University of Wisconsin, Madison - Observation of Anisotropy in the arrival direction distribution of Cosmic Rays above TeV energies with IceCube
The IceCube neutrino telescope, completed in December 2010,
is a cubic- kilometer scale detector buried under the
South Pole ice. Between May 2009 and May 2010, IceCube recorded 32 billion
of atmospheric muons generated in
air showers produced by cosmic rays in the TeV energy range. This high statistics
data sample can be used to look
for anisotropy in the arrival directions of the cosmic ray particles at the
per-mille level. IceCube observes, for the first
time in the southern hemisphere, an energy dependence in the Galactic cosmic
ray anisotropy up to a few hundred
TeV. This study shows that the same large-scale anisotropy observed at median
energies around 20 TeV is not present
at 400 TeV; the anisotropy observed at 400 TeV shows substantial differences
with respect to that at lower energy.
In addition to the large-scale features observed at 20 TeV in the form of strong dipole and quadrupole moments, the data include several localized regions of excess and deficit on scales between 10° to 30°. The features observed at both large and small scale are statistically significant, but their origin is currently unknown. In this talk we review the latest results from the IceCube neutrino telescope as well as some possible theoretical model to explain the observations. access to the talk
Prof. Norbert Wermes, University of Bonn - Pixel Detectors - trends and options for the future
Pixel detectors have been invented in the early 90s with the advancement of micro technologies. With the advent of the LHC, big vertex detectors have demonstrated that the pixel detector type is holding many of the promises it had made before. Meanwhile new, different or just improved variants of the pixel technology are being studied for their suitability for future experiments or experiment upgrades. The talk will address the various pro's and con's comparing hybrid and monolithic pixel technologies and their suitability for the different accelerator environments. access to the talk
Dr Philippe Mermod, Université de Genève, DPNC - The Search for the Magnetic Monopole
It has long been realised that the existence of a magnetic monopole would be sufficient to explain the quantisation of electric charge, and to symmetrise Maxwell's equations. Furthermore, the monopole is an essential ingredient in Grand Unification theories. Primordial monopoles would have been produced in the Early Universe and still be present today, either in cosmic rays or trapped in matter. Monopoles of accessible masses would also be pair-produced at high-energy accelerators. Their remarkable properties can be exploited to devise various means of direct detection. After reviewing the most recent monopole searches, whether at colliders, in flight or in matter, the prospects for new monopole searches at the LHC and elsewhere will be discussed. access to the talk
Dr Carsten Rott, Center for Cosmology and Astroparticle Physics (CCAPP), Ohio State University - The Search for Dark Matter with Neutrinos
Neutrino telescopes offer exciting opportunities for the indirect search for dark matter. They have a high discovery potential through striking signatures. Very competitive constraints on the dark matter self-annihilation cross section and scattering cross section with nucleons have been obtained through observations of the Milky Way and the Sun, respectively. After a review of on-going searches, with a particular focus on IceCube, I will discuss prospects for observing dark matter signals at current and next generation neutrino detectors. The talk will conclude by discussing new methodologies in dark matter searches such as the use of spectral and neutrino flavor information.
Dr Monica D'Onofrio, University of Liverpool - Searches for SUSY at the LHC: status and prospects
Supersymmetry is a theory that provides an extension of the Standard Model and naturally solves the hierarchy problem by introducing supersymmetric partners of the known bosons and fermions. The ATLAS and CMS collaborations are searching for SUSY particles in several final states, exploiting at best the excellent quality of the data delivered by the LHC and recorded by the experiments. I shall review the most recent results, with prospects for near and far future.
Semestre d'Automne 2011
|Date||Conférencier||Titre du séminaire et Annonce|
|21 Sep. 2011||Dr Sebastian Arrenberg, University of Zurich||Dark matter Search with the CDMS experiment|
|12 Oct. 2011||Prof. Carlo Giunti, INFN Torino||Towards 3+1 Neutrino Mixing|
|02 Nov. 2011||Dr Cinzia Da Via, University of Manchester, UK||Recent developments on 3D sensors|
|16 Nov. 2011||Prof. Karl Jakobs, University of Freiburg, Germany||Search for the Higgs Boson at the LHC|
|30 Nov. 2011||Dr Dominique Fortin, TRIUM, Vancouver, Canada||Searches for Exotic Physics with leptons with the ATLAS Detector|
The Cryogenic Dark Matter Search experiment (CDMS) employs a total of 30 germanium and silicon detectors at the Soudan Underground Laboratory to detect weakly interacting massive particles (WIMPs) via their scattering from the target nuclei. Previous CDMS results, released in December 2009, set the world leading limit on the spin-independent WIMP-nucleon cross section above WIMP masses of ~50 GeV/c2 assuming elastic scattering. In a subsequent analysis we investigated the inelastic dark matter scenario which was proposed to reconcile the disagreement between the results of DAMA/LIBRA and other existing dark matter search experiments. In order to maximize the sensitivity to this particular model a refined analysis in the range from 25 to 150 keV has been performed. Results emerging from this analysis will be presented. Moreover, preliminary results from a likelihood analysis of the CDMS data will be shown. access to the talk
I will review the recent experimental indications in favor of short-baseline neutrino oscillations. I will discuss their interpretation in the framework of neutrino mixing schemes with one or more sterile neutrinos which have masses around the eV scale. Taking into account also cosmological constraints, I will present arguments in favor of 3+1 neutrino mixing with one sterile neutrino at the eV scale. access to the talk
are a novel kind of silicon radiation sensors where electrodes are micromachined
inside the semiconductor substrate
rather than being processed on its surfaces.
This is possible by using Deep Reaction Io Etching, the same technique
used to Fabricate MEMS (Micro-Electro-Mechanical Systems). Properties of
this innovative design include extreme radiation hardness and high speed.
Several Industrial partners and Academic institutes successfully joined
together to accelerate the transition between the 3D R&D phase and
Industrialization. This seminar will discuss the state of the art of 3D,
its applications and potentials for the future. 3D will be used in the
first ATLAS upgrade in 2013.
access to the talk
Prof. Karl Jakobs, University of Freiburg, Germany - Search for the Higgs Boson at the LHC
One of the prime tasks of the physics programme of the LHC is the investigation of electroweak symmetry breaking. In the Standard Model the Higgs mechanism is invoked to give masses to the electroweak gauge bosons and fermions and to restore unitarity of the theory at high energies. Although the Higgs mechanism is one of the cornerstones of the Standard Model it is experimentally not validated and the associated Higgs boson has escaped detection so far.
data accumulated at the LHC in the years 2010/11 allow already to establish
tighter constraints on the allowed mass
the Higgs boson. In the present talk the strategies
for the search of the Higgs boson at the LHC are presented. The status of
the search is
primarily discussed for several analyses of the ATLAS data covering different
mass regions. In addition, the results based on the combination of individual
channels in ATLAS and the
results of the combination with the results of the CMS experiment are presented.
prospects for the Higgs boson search with more data and the potential of
of Higgs boson parameters are summarized.
access to the talk
With the large 5 fb-1 sample of pp collisions recorded in 2011, ATLAS has taken full advantage of the opportunity to explore new territory at the TeV scale. In this seminar, an overview of searches for new exotic particles is presented, with a special emphasis on signatures with leptons.
Semestre de Printemps 2011
|09 Mar. 2011||Dr William Bell, DPNC, University of Geneva||From charged-particle multiplicities to the top quark|
|30 Mar. 2011||Christoph Tunnel, University of Oxford||Software engineering for Particle Physics|
|06 Apr. 2011||Dr Sergio Gonzalez Sevilla, DPNC, University of Geneva||R&D for the ATLAS detector upgrade|
|13 Apr. 2011||Dr Jonathan Hays, Imperial College, London||Higgs searches at Tevatron|
|25 May 2011||Prof. Paolo Strolin, Università Federico II and INFN, Napoli||Muon radiography of volcanoes and the MU-RAY project|
|01 Jun. 2011||Dr Mark Rayner, DPNC, University of Geneva||A novel technique for characterizing the MICE muon beam and demonstrating its suitability for a muon cooling measurement|
|08 Jun. 2011||Prof. Andre Schoening, Univeristy of Heidelberg||A Novel Experiment for the Search muon -> eee|
|22 Jun. 2011||Prof. Alain Blondel, University of Geneva||Observation de candidats électron-neutrino dans l'expérience T2K|
A series of key experimental results from the ATLAS detector at the LHC are presented. These results include the first measurements of charged-particle multiplicities from inelastic proton-proton collisions, W boson production, and recent top cross-section results. The measurements were performed using part or most of the 2010 proton- proton data set, corresponding to a total luminosity of 45pb-1. The experimental methods involved in these measurements are discussed. Results are compared with recent theoretical predictions and possible 2011 measurements are outlined. access to the talk
Particle physicists rely heavily on programs which they develop themselves for their day-to-day responsibilities such as developing a high-level trigger, analyzing calibrations, or performing fancy fits. Within the last 10 years software engineering has matured from self- appointed gurus preaching coding rules over beers to peer-reviewed studies with data. What can we learn from industry? Which differences are intrinsic to the needs of physics and which are bad habits? In this talk I will discuss how our software challenges compare to industry and what they've learned that we could steal. I will use personal case studies from ATLAS, neutrino experiments, and accelerator experiments. How much does the programming language matter? Is an expert programmer really 10 times more productive than a non-expert? Does test-driven-development actually work? There will be something for both new and old programmers alike. access to the talk
The LHC foresees a major luminosity upgrade for around 2020, implying a harsher radiation environment and higher detector occupancies. The upgrade of the ATLAS experiment is planned to be done in two phases. In the so-called "Phase-1" an additional fourth Pixel layer will be integrated with a new beam-pipe. For "Phase-2", a complete new inner tracker must be built. The current layout assumes an all-silicon tracker with pixel detectors for the innermost layers and strip modules at higer radii. R&D activities are well under way in various fronts. For example, novel radiation-hard detector technologies and readout electronics are being developed, new power distribution schemes are being investigated and strip module prototypes are already being tested and evaluated in terms of electrical performance. In this talk, the status of the work towards an upgraded ATLAS detector is presented, with special emphasis devoted to the tracker. access to the talk
The search for the Higgs boson has occupied hundreds of physicists for more than a decade and remains one of the primary focuses of the global collider physics programme.
With running due to end later this year the Tevatron era is drawing to a close and the LHC is taking over the mantel of searching for this elusive particle.
The latest results in the search for the Higgs at the Tevatron will be presented together with the prospects for the full data set. access to the talk
Thanks to their penetration power, high energy muons generated in the interactions of cosmic rays with the Earth’s atmosphere offer the possibility to perform “muon radiographies” of geological structures and in particular volcanoes. The principle is similar to that of the imaging of the interior of human body through the observation of the absorption of X rays.
Muon radiography has been first applied in 1970 to the search of unknown burial chambers in the Chefren’s pyramid. In the years 2000, the technique has been successfully applied to volcanoes in Japan. Quasi-horizontal muons have provided spectacular radiographies of volcanoes’ edifices over rock thicknesses of the order of one kilometer.
The radiography of the upper part of volcanoes like Mt. Vesuvius or Stromboli implies the challenging task of observing the low flux of muons of such a high energy to be able to penetrate a larger rock thickness. This requires the development of instruments having a sensitivity larger by one order of magnitude or more. This implies correspondingly larger area and background rejection power.
project is presently developing a “muon telescope” based
on the use of plastic scintillator strips read by wavelength shifting fibers
and Silicon Photo-Multipliers (SiPM). The very low power consumption of the
SiPMs makes them suitable for the operation of the muon telescope in a volcanic
environment where the power supply may have to come from solar energy. The
R&D related to the use of SiPMs and the design of the readout electronics
is carried out in collaboration with physicists facing similar requirements
for experiments in Space. access
to the talk
The Muon Ionization Cooling Experiment is one lattice cell of a cooling channel suitable for conditioning the muon beam at the front end of a Neutrino Factory or Muon Collider. The beam line designed to transport muons into MICE has now been installed, and data was collected in 2010. In this talk I will present a novel single-particle phase space reconstruction technique, a first measurement of the emittance, and a simulation of the progress of the measured beam in the final experimental configuration.
The absence of lepton-flavor changing processes, like the non-observation of the radiative decay mu -> e gamma, has been a miracle since the dawn of the Standard Model of Particle Physics and lead to the introduction of the concept of lepton family numbers.
Several experiments in the last decade have shown clear evidence for neutrino oscillations. The neutrino mixing angles measured are known to be large. However, the discovery of lepton flavor violating (LFV) effects in the charged lepton sector is yet owing.
After motivating the search for LFV in general I will discuss the physics potential of a search muon -> eee with an increase of sensitivity by four orders of magnitude compared to previous experiments. Background studies for a detector exploiting " state of the art" detector technologies are presented. Emphasis will be given to the tracking system using mainly thin monolithic high voltage CMOS pixel detectors. access to the talk
L'expérience T2K vient d'annoncer l'observation de 6 candidats νe à SuperKamiokande pour un fond attendu de 1.5. La probabilité d'une fluctuation du bruit de fond est de 0.7 %. Ces événements peuvent être interprétés comme le résultat d'une oscillation νμ->νe.
Il s'agit de la première indication d'un angle θ13 de la matrice PMNS non nul. Ce résultat est compatible à 90% CL avec 0.03(0.04)< sin2 θ13< 0.28(0.34) pour δCP = 0 et une hiérarchie normale (inversée). Ce résultat est très important pour la suite du programme d'exploration de la violation de CP dans les neutrinos.
Semestre d'Automne 2010
|22 Sep. 2010||Dr Sebastian White, Brookhaven National Laboratory, BNL||New Physics with Leading Baryons at the LHC|
|29 Sep. 2010||Dr Gustav Wikström, DPNC, University of Geneva||T2K in the era of neutrino physics|
|13 Oct. 2010||Dr Bertrand Echenard, California Institute of Technology||Exotic Hadrons, Light Higgs and Dark Forces at BABAR|
|20 Oct. 2010||Prof. Jenny Thomas, University College London||The MINOS Experiment, Results and Future Plans|
|17 Nov. 2010||Dr Iain Bertram, Lancaster University||Results on CP-Violation in The Bs and Bd systems at the Tevatron|
|01 Dec. 2010||Dr Emiliano Mocchiutti, INFN, Trieste||PAMELA - A cosmic ray observatory in space|
Dr Sebastian White, Brookhaven National Laboratory, BNL - New Physics with Leading Baryons at the LHC
The leading baryon remnants in high energy proton-proton and nuclear collisions
carry a great deal of information. In the ATLAS experiment a new device for
high energy pp collider physics - the Zero Degree Calorimeter (ZDC)- has been
providing information from this kinematic region and ATLAS triggers since LHC
Previous high energy collider experiments have measured leading protons, albeit in a miniscule range of Feynman x, and this has led to the very productive field of hard diffraction. ATLAS ZDC measurements, instead, cover neutral leading baryon and photon production over the range 0.2<xF<1.0 and provide a wealth of information about correlations between the forward baryon sector and the central region. These data are of interest, particularly, for new topics, which become interesting at the very high energies accessed by the LHC. For example, due to the shrinking of the diffractive peak and the growth of the hard component in pp collisions at the LHC, there is growing interest in characterizing these collisions in terms of collision impact parameter as suggested by Bjorken and by Strikman et al.
This approach is, of course, familiar in Heavy Ion collider physics. Planned measurements of diffractive and non-diffractive photonuclear interactions during the upcoming ATLAS Heavy Ion run will employ the ZDC for triggering and data analysis.
The ATLAS ZDC addresses a number of interesting technical challenges. Not least of these is the 200W of continuous beam energy (5 Grad/year) which the LHC dumps into each detector at design luminosity.
The ZDC has far exceeded the time of flight performance of all other ATLAS detector subsystems. I will discuss the techniques used to obtain this high performance from sparsely sampled waveforms. access to the talk
Dr Gustav Wikström, DPNC, University of Geneva - T2K in the era of neutrino physics
The T2K neutrino oscillation experiment has been taking data since the beginning of the year, and several neutrino beam events have been observed in the Super-K detector, 295 km from the J-Parc accelerator and the ND280 detector. The main goals of the experiment are to measure the disappearance of muon neutrinos and the appearance of electron neutrinos, as well as precise measurements of neutrino-nucleon interactions. A positive appearance signal would make it possible to search for neutrino CP-violation. The expected sensitivity to oscillation parameters are presented in the context of the many unanswered questions that prevail in the neutrino sector of the standard model. access to the talk
Dr Bertrand Echenard, California Institute of Technology - Exotic Hadrons, Light Higgs and Dark Forces at BABAR
From spectroscopy to search new physics, B-factories have explored many exciting topics besides establishing CP-violation in B decays. We will review recent results on spectroscopy, exotic hadrons and search for light Higgs. Current searches for dark forces and GeV-scale dark matter particles will also be discussed. access to the talk
Prof. Jenny Thomas, University College London - The MINOS Experiment, Results and Future Plans
The MINOS experiment has been taking data in the NuMI beam at FNAL for 4 years and has the worlds most precise measurements of a number of neutrino parameters. I will summarise the status of the MINOS results and talk about the near term plans for the next two years. access to the talk
Dr Iain Bertram, Lancaster - Results on CP-Violation in The Bs and Bd systems at the Tevatron access to the talk
Results will be presented from the investigation of CP-violation in B mesons at the Tevatron. The evidence for an anomalous likes-sign dimuon charge asymmetry will be presented, along with the latest results on CP violation in the Bs -> J/Psi Phi system. The implications of these results and the possibility of confirming them in the future will also be discussed.
Dr Emiliano Mocchiutti, INFN, Trieste - PAMELA - A cosmic ray observatory in space
On the 15th of June 2006, the PAMELA satellite-borne experiment was
launched from the Baikonur cosmodrome and it has been collecting data
since July 2006. The apparatus comprises a time-of-flight system, a
silicon-microstrip magnetic spectrometer, a silicon-tungsten
electromagnetic calorimeter, an anticoincidence system, a shower tail
counter scintillator and a neutron detector. The combination of these
devices allows precision studies of the charged cosmic radiation to be
conducted over a wide energy range (100 MeV - 100's GeV) with high
statistics. The primary scientific goal is the measurement of the
antiproton and positron energy spectrum in order to search for exotic
sources, such as dark matter particle annihilations. PAMELA is also
testing cosmic-ray propagation models through precise measurements of
the antiparticle energy spectrum and precision studies of light nuclei
and their isotopes. Moreover, PAMELA is investigating phenomena
connected with solar and earth physics.
Latest results after four years of data-taking will be presented.
access to the talk
Semestre de Printemps 2010
|10 Mar. 2010||Prof.Franco Bradamante, University and INFN Trieste||The COMPASS Experiment at CERN: achievements and outlook|
|17 Mar. 2010||Prof. Hafeez Hoorani, Scientific Director, SESAME, Quaid-E-Azam University||Status of SESAME Project|
|14 Apr. 2010||Dr Marc Schumann, Université de Zurich||Dark Matter and the XENON Experiment|
|28 Apr. 2010||Prof. Walter Oelert, Research Center Jülich||On our way to anti-hydrogen at rest|
|12 May 2010||Dr Aldo Antognini, CREMA Collaboration, Max Planck Institute, Germany||Measurement of the Lamb shift in muonic hydrogen: the proton radius puzzle|
Prof. Franco Bradamante, University and INFN, Trieste - The COMPASS Experiment at CERN: achievements and outlook
The COMPASS Collaboration has set up a modern spectrometer at CERN to investigate two complementary aspects of hadron physics, the spin > structure of the nucleons and the light quark spectrum of hadrons. The experiment is taking data since 2002.
The spin structure of the nucleon has witnessed a real renaissance in the past 20 years, and COMPASS has measured both longitudinal and transverse spin effects using polarized proton and deuteron targets and a 160 GeV muon beam. Important contributions have been given to the assessment of the quark and gluon contribution to the nucleon spin, and establishing new properties of the parton distribution functions and of the fragmentation functions related to the transverse spin. Using hadron beams, of ~ 200 GeV, in 2008 and 2009 data have been taken on a liquid hydrogen target in search of glueballs and other exotic hadronic states.
An overview of the main accomplishments of the experiment will be given, as well as a mention of the future plans which are presently being formulated. access to the talk
Dr Hafeez Hoorani, Scientific Director, SESAME - Status of SESAME Project
Synchrotron-light for Experimental Science and Applications in Middle East SESAME is a project, which is established under auspices of UNESCO as intergovernmental organization with following members: Bahrain, Cyprus, Egypt, Iran, Israel, Jordan, Pakistan, Palestine Authority, and Turkey. The German Government as a gift has donated the injector and booster for SESAME after dismantling of BESSY in Berlin. The SESAME team will build the storage ring.
SESAME is a third generation light source with beam energy of 2.5 GeV, beam current of 400 mA, emittance 26 nm.rad and circumference of 133.2 m. It is under construction close to Amman – Jordan and will become operational end of 2012 or beginning of 2013. SESAME contains 16 straight sections out of which 13 straight sections are available for placing insertion devices such as undulator and wigglers.
An extensive scientific
programme has been established with the help of Scientific Advisory Committee
(SAC) and the Beamline Advisory Committee (BAC). From the
beginning 7 beamlines are planned for Phase – I covering diverse areas
of scientific interest such as: SAXS/WAXS, PX, IR, Soft X-ray, Powder Diffraction,
XRF/XAFS and Atomic, Molecular spectroscopy (AMO) beamline. SESAME once operational
will be a very competitive machine in the category of third generation light
Dr Marc Schumann, Université de Zurich - Dark Matter and the XENON Experiment
There is convincing astrophysical and cosmological evidence that most of the matter in the Universe is dark: It is invisible in every band of the electromagnetic spectrum. Weakly interacting massive particles (WIMPs) are promising Dark Matter candidates that arise naturally in many theories beyond the Standard Model. Several experiments aim to directly detect WIMPs by measuring nuclear recoils from WIMPs scattered on target nuclei.
In this talk, I will give an overview on Dark Matter and direct Dark Matter detection. Then I will focus on the XENON100 experiment, a 2-phase liquid/gas time projection chamber (TPC) that is installed underground at the Gran Sasso Underground Lab (LNGS), and the future of the XENON project. Access to the talk
Prof. Walter Oelert, Research Center Jülich - On our way to anti-hydrogen at rest
Trapped cold atoms of anti-hydrogen are optimal for testing possible CPT violations in comparison of spectral lines and gravitational effects on matter and anti-matter.
For this reason it is mandatory to optimize the properties of the clouds of anti-protons and positrons used to produce the anti-hydrogen atoms. The ATRAP-collaboration at CERNs AD did perform such experiments by studying the temperature of these clouds and their stability at different conditions. Though detailed tests have been performed to verify the trapping of anti-hydrogen atoms in a magnetic gradient field no statistically significant signal was detected yet. Results of theses investigations and further experimental developments will be presented. Access to the talk
Dr Aldo Antognini , CREMA Collaboration, Max Planck Institute, Germany - Measurement of the Lamb shift in muonic hydrogen: the proton radius puzzle
At the Paul Scherrer Institut, Switzerland, we have measured several 2S-2P transition frequencies in muonic hydrogen (µp) and deuterium (µd) by means of laser spectroscopy. This results in an order of magnitude improvement on the rms charge radius values of the proton and the deuteron. Additionally the Zemach radii and the deuteron polarizability are also inferred. The new proton radius value is deduced with a relative accuracy of 0.1% but strongly disagrees from CODATA.
The origin of this discrepancy is not yet known. It may come from theory of the muonic hydrogen energy levels (used to deduce the new value), or from problems in hydrogen spectroscopy experiments or hydrogen energy level theory (both used to deduce the CODATA value). The decrease of the proton value uncertainty opens the way to compare the hydrogen energy levels predictions with high-precision (ur = 10-12 ...-14) measurements to an unprecedented accuracy. This will stimulate progress in the understanding of the simplest atom and its related bound-state QED theory.
measurements and results will be presented. Additionally the key issues regarding
the observed discrepancy will be given together with
the impact of these measurements on bound-state QED test and fundamental constants.
Access to the talk
Semestre d'Automne 2009
|Dr Philippe Mermod, Université d'Oxford||Long-lived particle searches at colliders|
|25 nov. 2009||Dr Ilias Efthymiopoulos, CERN||Highlights of the European Strategy Workshop for Future Neutrino Physics|
|09 dec. 2009||Prof. Arno Straessner, Technische Universitaet Dresden||The Origin of Mass|
Dr Philippe Mermod, Université d'Oxford - Long-lived particle searches at colliders
of exotic long-lived particles would address a number of important questions
in modern physics such as the origin and
composition of dark matter
and the unification of the fundamental forces. This talk will focus on searches
for long-lived charged massive particles, where "charged" refers
to the magnetic, electric or colour charge. Previous searches at the LEP and
Tevatron Colliders allowed to put mass and cross section limits on various
kinds of long-lived particles, such as Magnetic Monopoles and metastable leptons
and up-type quarks. The new energy regime made available at the LHC will probe
physics regions well beyond these limits. For instance, a new long-lived particle
with mass 300 GeV carrying colour charge is expected to be copiously produced
at the LHC and leave striking events in the detectors. I will outline a signature-based
search strategy for long-lived massive hadrons in early ATLAS data.
Fichier .pdf de la présentation
Dr Ilias Efthymiopoulos, CERN - Highlights of the European Strategy Workshop for Future Neutrino Physics
Beginning of October 2009, a 3 day workshop was organized at CERN to consider the future neutrino physics with emphasis on the development work required for accelerator based neutrino physics. The high attendance and the quality of presentations and discussions made it a success also showing the dynamism and motivation of the European neutrino physicist community. The CERN workshop was an important step in a process where ongoing R&D projects and Design Studies in Europe were presented. At the same time it allowed scientific bodies, like the Panel on Future Neutrino Facilities established by the Scientific Policy Committee in December 2008 at the request of the CERN Council, to collect input and opinions of the European neutrino physics community in view of decisions to come. In the seminar selected highlights from the presentations and the summary discussions will be presented.
Dr Arno Straessner, Technische Universität, Dresden - The origin of mass
What is the origin of mass for elementary particles ? Since many years, this question motivates physicists to build large collider experiments. The most recent examples are the ATLAS and CMS detectors at the Large Hadron Collider at CERN. The currently well tested Standard Model predicts the existence of a new particle which has not yet been detected experimentally: the Higgs boson. It is the manifestation of the Higgs mechanism, which creates masses of elementary particles in a theoretically attractive way. The LHC experiments will search for the Standard Model Higgs boson, as well as for further Higgs bosons predicted by a super-symmetric extension of the model.
In the lecture, the general concept of mass in particle physics, as well as the relationship to macroscopic masses will be explained. After a short introduction to the physics of Higgs bosons, the experimental strategy of Higgs boson searches at the LHC will be presented. Eventually, perspectives for future activities, like the measurement of Higgs properties at the LHC and its successor, the super-LHC, will be given.
Semestre de Printemps 2009
|25 Feb. 2009||Francesca Volpe, MPIK, Max-Planck-Institute for Nuclear Physics, Heidelberg||Physics insights from recent HESS AGN observations|
|11 Mar. 2009||Dr Alison Lister, University of Geneva||What can we learn from top quark physics at CDF ?|
|25 Mar. 2009||Prof. Gustaaf Brooijmans, Columbia University||Hunting for the Higgs with D0 at the Tevatron|
|08 Apr. 2009||Dr Pierre PUGNAT, CNRS - GHMFL (Grenoble High Magnetic Field Laboratory)||The OSQAR Experiments at CERN to probe QED & Astroparticle Physics from the Photon Interaction with a Magnetic Field|
|29 Apr. 2009||Dr Mihail Chizhov, Physics Department, Sofia University, Bulgaria||Search for spin-1 excited bosons at the LHC|
|13 May 2009||Prof. Olaf Reimer, Stanford University||Observing the extreme universe with the Fermi Gamma-ray Space Telescope|
|27 May 2009||Dr Thierry Lasserre, CEA, Saclay||Status report on Double Chooz|
|17 Jun. 2009||Dr Fanny Dufour, Université de Genève, DPNC||Long baseline neutrino detectors for T2KK: Water Cherenkov versus Liquid Argon|
Dr Francesca Volpe MPIK, Max-Planck-Institute for Nuclear Physics, Heidelberg - Physics insights from recent HESS AGN observations
The extragalactic sources are still the most powerful, variable and brightest objects in the VHE gamma-ray sky. The improved sensitivity of the new generation of ground-based instruments have increased the VHE emitting population, providing information about cosmology and giving new clues about particle acceleration mechanisms at play in active galactic nuclei.
Emphasis will be put on the contribution of the H.E.S.S. experiment to the temporal variability of extragalactic gamma-ray sources, including an update on the most recent detections and on the giant flares from PKS 2155-304.
Dr Alison Lister, University of Genevar - What can we learn from top quark physics at CDF?
After a brief introduction to (or reminder of) the Tevatron accelerator and
the CDF experiment, we will delve into the depths of how a top physics analyses
is done at CDF. We will follow through how each of the pieces used to measure
the top quark cross section are obtained or measured and finally how all the
pieces are put together to get a measurement as precise as the current best
We can then use that analysis infrastructure to search for new physics that appears in the top event sample, in this particular case by describing a search for fourth generation top-like quarks, one of the few CDF analyses to see something "fishy" we don't fully understand.
This seminar will aim to illustrate more the process of carrying out a measurement at a hadron collider than of showing the whole array of top physics results from CDF. As a result of this, the talk will be targeted implicitly at younger scientists who have maybe not yet been able to see data, or anyone from outside accelerator-based experiments who is curious to know how we actually get to our results we show at conferences.
Prof. Gustaaf Brooijmans, Columbia University - Hunting for the Higgs with D0 at the Tevatron
The search for the Higgs boson is one of the most important endeavors in current experimental particle physics. At the eve of the LHC start, the Tevatron is delivering record luminosity allowing both CDF and D0 to explore a new region of possible Higgs masses. In this seminar, the techniques used to search for the Higgs boson at the Tevatron will be explained, limiting factors will be examined, and the sensitivity in the various channels will be reviewed. The newly excluded values of the standard model Higgs mass will be presented.
Dr. Pierre PUGNAT, CNRS - GHMFL (Grenoble High Magnetic Field Laboratory) - The OSQAR Experiments at CERN to probe QED & Astroparticle Physics from the Photon Interaction with a Magnetic Field
A collaboration between eight European Institutes and CERN is working on a new “2-in-1”, laser-based Particle Physics experiments for Optical Search of QED vacuum magnetic birefringence, Axions and photon Regeneration (OSQAR). Since its prediction in 1936 by Euler, Heisenberg and Weisskopf in the earlier development of the Quantum Electrodynamic (QED), the Vacuum Magnetic Birefringence (VMB) is still a challenge for optical metrology. Contributions to the VMB could also arise from new light scalar/pseudo-scalar particles like axions that couple to photons and this would manifest itself as a sizeable deviation from the pure QED prediction. On one side the interest in axion, providing the most plausible solution to the so-called strong-CP problem, lies beyond Particle Physics and overlaps with Cosmology since such particle is also considered as a serious dark matter candidate. On the other side, the domain of Physics that will be investigated is guaranteed by the QED, which aimed to be tested down to the 10-22 level by measuring the relative difference of the vacuum refractive indices in a 9.5 T field. The measurement for the first time of this “vacuum anomaly” of the refraction index is in the same line than the measurement of the anomalous magnetic moment of the muon performed in the early years of CERN by G. Charpak et al. (1961). By re-using major achievements of the Large Hadron Collider (LHC), like superconducting dipoles and test infrastructure, OSQAR offers a unique opportunity to launch at CERN an innovative research programme in the emerging field of laser-based Particle/Astroparticle Physics. The status of the OSQAR project will be reported together with the theoretical background, first results (published in Phys. Rev. D 78, 092003, 2008) as well as short and long term perspectives.
Dr Mihail Chizhov, Physics Department, Sofia University, Bulgaria - Search for spin-1 excited bosons at the LHC
I will discuss the resonance production of new type spin-1 excited bosons, Z*, at hadron colliders. They can be observed as a Breit-Wigner resonance peak in the invariant dilepton mass distribution in the same way as the well-known hypothetical gauge bosons, Z'. This makes them very interesting objects for early searches with the LHC first data. Moreover, they have unique signatures in transverse momentum and angular distributions, which allow to distinguish them from other resonances.
Prof. Olaf Reimer, Stanford University - Observing the extreme universe with the Fermi Gamma-ray Space Telescope
The Fermi Gamma-ray Space Telescope (FGST, formerly GLAST) is an international observatory-type satellite mission with a physics program spanning from gamma-ray astronomy to particle astrophysics and cosmology. FGST was launched on June 11, 2008 and is successfully conducting science observations of the high-energy gamma-ray sky since August 2008. A varienty of discoveries has been made already, including monitoring rapid blazar variability, the existence of GeV gamma-ray bursts, and numerous new gamma-ray sources of different types, including those belonging to previously unknown gamma-ray source classes like msPSRs, globular cluster and non-blazar-type AGN. Fermi-LAT, the observatory's main instrument, also performed an accurate measurement of the diffuse gamma-radiation which clarifies the controversially discussed "GeV excess" reported by EGRET almost 10 years ago, detected of gamma-radiation from molecular clouds, proved that radio-quiet PSR constitute a substantial fraction among Galactic gamma-ray sources, and measured the cosmic GeV to TeV electron spectrum with high precision. An overview of the observatory status and already accomplished scientific results will be presented.
Dr Thierry Lasserre, CEA, Saclay - Status report on Double Chooz
The measurement of the last undetermined neutrino mixing angle theta-13 is the main goal of the next generation of neutrino oscillation experiments. The present limit is driven by the result of the Chooz experiment. Double Chooz is the next generation reactor experiment aiming to improve the current best sensitivity of the CHOOZ experiment by roughly one order of magnitude. The aimed sensitivity requires both the statistical and systematical errors to be significantly reduced with respect to past reactor experiments. In particular, the success of the project depends on the reduction of the systematics, made possible by the installation of a near identical detector and by the improvement of the detector design. The experimental concept will be presented in details. The first detector is now under construction since May 2008. The data taking is scheduled from end-2009. The second detector will be commissioned end in 2011.
Fanny Dufour, DPNC, Université de Genève -
Long baseline neutrino detectors for T2KK: Water Cherenkov versus
In this talk,
I will present two proposals of long baseline neutrino experiments that are
currently being investigated for the Tokai to Kamioka
and Korea setup. The assumed neutrino beam is a 1.66 MW beam coming from the
Tokai accelerator and providing 2.6 * 1021 protons on target per year. Two
different detector technologies have been proposed to study this beam.
Either water Cherenkov, or liquid Argon, I will present a comparison of the
assumptions and expectations from these two proposals.
Fichier .pdf de la présentation
Semestre d'Automne 2008-2009
|Dr Gersende Prior, Lawrence Berkeley National Laboratory||The Sudbury Neutrino Observatory: probing the Sun from 2 km underground|
|29 Oct. 2008||Dr Michel Sorel, IFIC, (CSIC and University of Valencia)||Precision measurements of low-energy neutrino-nucleus interactions with the SciBooNE experiment at Fermilab|
|19 Nov. 2008||Dr Filip Moortgat, ETH Zurich||Early searches for new Physics at the CMS experiment|
|10 Dec. 2008||Prof. Drew Baden, University of Maryland||Kinematics at Hadron Colliders|
|17 Dec. 2008||Dr Michela Prest, Universit`a degli Studi dell'Insubria, sede di Como||Bent crystals: a long story and its new frontiers|
Dr Gersende Prior, Lawrence Berkerley National Laboratory - The Sudbury Neutrino Observatory: probing the Sun from 2 km underground
The Sudbury Neutrino Observatory (SNO) experiment, located in a mine in Canada, started in 1999 and took solar-neutrino data for nearly seven years.
The experiment operated in three distinct phases reflecting different experimental configurations. Results from its first two phases have provided revolutionary insights on the neutrino properties and have verified our understanding of the energy production in the sun. The analysis of data from the final phase of the experiment, during which an array of special counters was deployed to enhance the measurement of solar neutrino flux, has been completed.
After an introduction on neutrinos and the SNO detector, I will discuss briefly the results from the first two phases and present in details the results of the third and final phase of the SNO experiment.
Dr Michel Sorel, IFIC (CSIC and University of Valencia) - Precision measurements of low-energy neutrino-nucleus interactions with the SciBooNE experiment at Fermilab
Do all modern accelerator-based neutrino experiments need to make use of kiloton-scale detectors and decade-long exposure times? In order to study the full pattern of neutrino mixing via neutrino oscillation experiments, the answer is probably yes, together with powerful proton sources. Still, to push the sensitivity of future neutrino oscillation searches into unchartered territory, those are necessary, but not sufficient, ingredients. In addition, accurate knowledge of neutrino interactions and neutrino production is mandatory. This knowledge can be acquired via small-scale and short-term dedicated neutrino experiments, such as SciBooNE. SciBooNE is a new neutrino experiment at Fermilab that has been designed to provide precision neutrino-nucleus cross-section measurements in the few-GeV neutrino energy range, where most future accelerator-based neutrino experiments are expected to operate. In this talk, a taste of ongoing analyses and preliminary results from SciBooNE will be given, together with their relevance for future neutrino oscillation studies.
Dr Filip Moortgat, ETH Zurich - Early searches for new physics at the CMS experiment
The CMS experiment at the LHC will provide unprecedented opportunities to discover new forms of matter and energy. This talk will first introduce the CMS experiment, its physics potential and general analysis strategy. It is followed by examples of possible searches for new phenomena in CMS, including Higgs, SUSY, and other exotic particles, with early LHC data.
Prof. Drew Baden, University of Marylan - Kinematics at Hadron CollidersExoplanets and quarks
I will review the kinematics of hadron collisions, especially relevant on the eve of the LHC startup. A variety of topics will be covered, meant to be useful for those not familiar with the origins and details of these considerations.
Dr Michela Prest, Universit`a degli Studi dell'Insubria, sede di Como - Bent crystals: a long story and its new frontiers
When a particle physicist hears the world “crystal”, he usually
thinks of calorimeters, silicon detectors, a state of matter. When he hears the word “magnet”,
he thinks of bulky, heavy objects.
In 1976, E. H. Tsyganov experimentally demonstrated how a bent crystal 1 mm
thick, a couple
of mm wide and a few cm high can steer particles as a dipole of several tens
Crystals and the channeling phenomena have been studied for around 30 years. Hadron beam collimation has been immediately identified as their main application and the understanding of the physics of crystals and their experimental study have proceeded in parallel, discovering new phenomena and requiring new technological achievments.
This seminar describes the role of bent crystals in collimation in general and for the second phase of LHC in particular giving an insight of the physics of crystals. It will also revise the topic of radiation production by light particles in bent crystals which is still an open field both from the theoretical and experimental points of view and which would be a real breakthrough in several fields, from the production of positron sources for the Linear Collider to the generation of intense gamma beams for medical applications.
Semestre de Printemps 2008
|20 Feb. 2008||Dr Ties Behnke, DESY FLC||The International Linear Collider: a global project for the future of particle physics|
|19 Mar. 2008||Prof. Michelangelo Ambrosio, INFN, Naple||Use of Multi-Walled Carbon Nanotubes for UV radiation detection|
|14 May 2008||Dr Michel Buénerd, Laboratoire de Physique Subatomique et de Cosmologie, Grenoble||CREAM, une expérience d'étude du rayonnement cosmique nucl éaire à haute énergie entre 1 et 1000TeV|
|21 May 2008||Prof. Dr. Reiner Krücken, Technische Universität München||NuSTAR: Structue and Dynamics of exotic nuclei at FAIR|
Dr Ties Behnke, DESY, FLC - The International Linear Collider: a global project for the future of particle physics
The International Linear Collider, ILC, is planned in a world-wide collaboration to be the next big collider after the LHC. The ILC will focus on precision - it will built upon the view of the Terascale physics which we will develop from the LHC results, and carry this further by adding precision measurements.
Over many years scientists have developed the foundation for the ILC proposal: a superconducting linear accelerator reaching energies between 500 GeV and 1 TeV. In parallel the requirements of unprecendented precision measurements has forced the experimental community to develop new detector concepts and event reconstruction techniques.
In this talk the state of the ILC project worldwide will be discussed, with a special focus on the planning of experiments for the ILC.
Prof. Michelangelo Ambrosio, INFN, Naple - Use of Multi-Walled Carbon Nanotubes for UV radiation detection
Optical and electrical properties of carbon nanotubes (CNT) have been widely investigated in the last years in view of their applications like: photo detection, solar cells, nano-electronics, opto-electronics, and so on. Sensitivity of Single-Walled CNT (SWCNT) to IR radiation has been demonstrated by different authors. Although the large interest in photo-sensitive properties of nanotubes, most of the work has been done on SWCNTs. The distribution of electronic states and electronic transitions is much more difficult to be predicted in MWCNTs than in SWCNTs. This makes, in fact, difficult any comparison between experimental work and theoretical predictions when Multi-Walled CNTs are used. However, interesting photocurrent properties have recently been observed also in samples containing Multi-Walled CNTs.
In this talk we report on measurements of CNT sensitivity to the radiation and on the realization and characterization of a prototype light detector based on MWCNTs. The results suggest that, despite the difficulty in modelling, the complex electronic structure of MWCNTs could be of advantage for the photosensitivity of CNTs-based devices by broadening the photo-response spectrum through the increasing of the possible electronic configurations and transitions.
Dr Michel Buenerd, Laboratoire de Physique Subatomique et de Cosmologie, Grenoble - CREAM, une expérience d'étude du rayonnement cosmique nucléaire à haute énergie entre 1 et 1000TeV
L'expérience CREAM (Cosmic Ray Energetics and Mass) a volé sous un ballon au-dessus du continent Antarctique en décembre-janvier derniers. L'exposé comprendra une présentation des objectifs du programme scientifique, une description générale de l'instrumentation, plus détaillée pour l'imageur Cherenkov, et une narration illustrée de la préparation du vol de CREAM en Antarctique, du lancement du ballon, du déroulement du vol avec quelques résultats en ligne, ainsi qu'une évocation de la vie à McMurdo.
Prof. Dr. Reiner Krücken, Technische Universität München - NuSTAR: Structue and Dynamics of exotic nuclei at FAIR
The Facility for antiproton and ion research (FAIR) will be constructed as an internation research facility in Darmstadt during the next 7 years. The research program covers a broad range of topics from the Physics of stored Antiprotons and highly charged atoms, plasma physics over exotic nuclei and nuclear astrophysics to hadron spectroscopy with antiprotons and the search for the triple point the QCD phase diagramm. In this talk the focus will be on the exciting opportunities to access nulcei far away from the valley of stability with a broad range of methods to study their structure and dynamics. Aside from our aim to understand the changes in shell structure and new modes of excitation of such exotic nuclei, these nuclei often play a role in the astrophysical processes of element synthesis. The talk will highlight the Nuclear Strucutre, Astrophysics, and Reactions (NuSTAR) facility and, using some examples, the major thrust of its physics program.
Semestre d'Automne 2007-2008
|26 Sep. 2007||Dr Phillip Urquijo, University of Melbourne||Precision determinations of |Vcb| and |Vub||
|03 Oct. 2007||Dr Silvio Orsi, INFN Roma Tor Vergata||The first year in orbit of the PAMELA space experiment|
|17 Oct. 2007||Dr Patrick Huber, CERN||Neutrinos - where we stand and where to go|
|31 Oct. 2007||Prof. Adrian Biland, ETH, Zurich||Very High Energy Gamma-ray Astronomy with the MAGIC Telescope|
|14 Nov. 2007||Dr Klaus Kirch, PSI, Villigen||The electric dipole moment of the neutron|
|28 Nov. 2007||Dr R. Smirnov-Rueda, Complutense University, Espagne||Manifest non-locality of bound electromagnetic fields in near zone of radiating sources: experimental observation|
|12 Dec. 2007||Prof. Drew Baden, University of Maryland||Kinematics
at Hadron Colliders
Attention ! Séminaire annulé et reporté à 2008
|30 Jan. 2008||Prof. Phil Yock, University of Auckland||Exoplanets and quarks|
Dr Phillip Urquijo, University of Melbourne - Precision determinations of |Vcb| and |Vub|
The success of the B factories has dramatically improved our
understanding of CP violation. The search for clear signs of new physics through
measurements of CP violation is limited by understanding of the CKM elements
|Vub| and |Vcb|. Improvement of our knowledge of the least well known CKM parameter,
|Vub|, therefore directly translates to a more stringent test of the Standard
Model. The prodigious samples of B meson decays available at the B factories,
along with advances in the theory involving semileptonic B decays, have been
used to provide a determination of both, |Vcb| and the b-quark mass, with a
precision of 1%, and bring the precision of |Vub| well below 10%.
The experimental and theoretical issues surrounding the determination of |Vub| and |Vcb| are complex and sometimes controversial. More recently, focus has been placed on ensuring accurate determinations of the b-quark mass using only semileptonic B decays, discarding the poorly understood radiative B decays.
The use of a variety of strategies for determining these CKM matrix elements provides important cross-checks on the theoretical uncertainties that in most cases dominate the overall uncertainties of |Vub| and |Vcb|. I will present various measurements of semileptonic B decays at Belle, and how they have meshed together to provide precision measurements of the CKM matrix element |Vcb|, the b-quark mass, and a better understanding of CKM matrix element |Vub|. I will also discuss important recent developments in the approach to the inclusive determination of |Vub|, which may have resolved the ~3 sigma discrepancy with measurements of the CP violation phases, and exclusive |Vub| determinations.
Dr Silvio Orsi, INFN Roma Tor Vergata- The first year in orbit of the PAMELA space experiment
The satellite-borne PAMELA experiment is designed to study charged particles in the cosmic radiation with a particular focus on antiparticles. PAMELA is mounted on the Resurs DK1 satellite that was launched from the Baikonur cosmodrome in Kazakhstan on June 15th 2006 and has a lifetime of at least 3 years. The PAMELA apparatus comprises a time-of-flight system, a magnetic spectrometer, a silicon-tungsten electromagnetic calorimeter, an anticoincidence system, a shower tail catcher scintillator and a neutron detector. PAMELA is performing indirect dark matter search through a detailed study of the positron and antiproton spectra (50MeV-270GeV and 80MeV-190GeV respectively). It also searches for antimatter (e.g. antiHe), studies the light nuclei component of the cosmic radiation, performs studies of cosmic ray propagation, of solar physics and solar modulation, and searches for local sources (through the study of the electron spectrum up to 2TeV). The talk will focus on the detector performances and on the preliminary results from the first year of operation.
Dr Patrick Huber, CERN - Neutrinos - where we stand and where to go
Neutrinos are enigmatic particles which have provided us with one of the clearest proofs for physics beyond the Standard Model of particle physics, so far. At the same time they are valuable probes of astro-physics and fundamental symmetries. The more we learn about the intrinsic properties of this particle the better we will be able to exploit its potential as a messenger of possibly exotic phenomena which otherwise would remain undetected. I will give a brief review of the current status of neutrino physics and introduce the open questions in the field. The emphasis in the second part of my talk will be on a tentative road map for addressing these questions with a focus on oscillation physics.
Prof. Adrian Biland, ETH, Zurich - Very High Energy Gamma-ray Astronomy with the MAGIC Telescope
Since the latest Cherenkov Telescopes started regular data-taking in 2004, the field of Very High Energy (VHE) Astronomy has drastically changed. The VHE sky is far richer than expected, and more than 50 sources have been found at energies above ~100 GeV. These sources belong to several classes of astronomical objects, e.g. Supernova Remnants, Plerions, X-ray Binaries as well as different classes of Active Galacic Nucleii (AGN). But many enigmatic VHE sources have no known counterpart, i.e. they are very bright above 100 GeV, while must be rather dim in other wavelengths.
The recent discovery of very fast VHE flux variations in AGNs indicate the potential to be able to test even most fundamental physics questions like effects predicted by some Quantum-Gravity models.
In my talk I will explain how Cherenkov telescopes work and show some selected results from MAGIC, the worlds largest Cherenkov telescope. Additionally, I will give a brief overview about the (near?) future plans for the next generation of VHE observatories.
Dr Klaus Kirch, PSI, Villigen - The electric dipole moment of the neutron
The electric dipole moment of the neutron (nEDM) has been searched for since the 1950s, improving the experimental sensitivity over the years by more than 6 orders of magnitude. A finite value of the nEDM would violate parity and time reversal symmetry and - invoking the CPT theorem - also CP. CP-violation, additional to the one known already, is needed in order to explain the observed baryon asymmetry of the universe. While in the electro-weak part of the Standard Model the nEDM is still another 6 orders of magnitude below the experimental limit, the strong interaction as well as, e.g. supersymmetric, extensions of the Standard Model foresee large CP-violation, and possibly lead to a finite nEDM. The nonobservation of the nEDM therefore lead to the " strong CP problem" and the "susy CP problem".
The progress to set up a new source of ultracold neutrons at PSI and the planned improved search for the nEDM at this source is described. As a byproduct, the first direct experimental limit on neutron -- mirror-neutron oscillations has been recently measured and will be reported.
Dr R. Smirnov-Rueda, Complutense University, Espagne - Manifest non-locality of bound electromagnetic fields in near zone of radiating sources: experimental observation
locality (causality) is referred as impossibility of superluminal propagation.
The creation of Quantum Mechanics (QM) led to
theorem which in the most general form sorted out QM predictions of strong
correlations between space-like separated systems from probabilities of measurement
outcomes calculated on the basis of local realism. EPR-type experiments gave
support to QM predictions, casting doubts on standard locality. Since then
common view has it that the quantum realm involves some type of misterious
non-locality because it has no analogy in the classical worldview.
As response to the above-mentioned controversy on non-locality we propose a novel approach which concerns only classical relativistic field theory. We found that the actual experimental verification of the standard locality within domains of classical electromagnetism is essentially incomplete since it does not take into account the internal structure of EM field as a superposition of bound and radiation components. Any ideally rigorous test of EM field causality must be based on individual tests for both components so that our experimental procedure made a clear distinction between the near and the far zones where bound and radiation fields are dominant, respectively. Measurements were carried out in two different configurations between emitting and receiving antennas at 125 MHz (??2.5 m) clearly showing that the propagation rate of bound EM fields highly exceeds the velocity of light in the near zone but tends to c in far zone. It might indicate on a possible constraint on locality within transition from QM to classical phenomena.
Prof. Drew Baden, University of Marylan - Kinematics at Hadron CollidersExoplanets and quarks
I will review the kinematics of hadron collisions, especially relevant on the eve of the LHC startup. A variety of topics will be covered, meant to be useful for those not familiar with the origins and details of these considerations.
Prof. Phil Yock, University of Auckland - Exoplanets and quarks
The search for Earth-like extra-solar planets is one of the forefront areas of astronomy today. The NZ/Japan MOA collaboration uses the gravitational microlensing technique at high magnification. When the magnification exceeds 50, Earth-mass planets orbiting the lens star at distances ~ 2-3 AU are detectable. Twenty-eight events with magnification > 50 were found by MOA in 2007. These will be briefly reviewed, together with earlier events in which planets were detected, and one in which the shape of a star was measured.
The mathematics of gravitational microlensing is comparable to that of Rutherford scattering, which underpins current research in particle physics. Recent data from CERN on hadron production in ?-? interactions exceed the predictions of QCD by an order of magnitude at high pT. The amplitude for the process is asymptotically proportional to the sum of the squares of the charges of quarks. The data appear reminiscent of Rutherford’s old results, and suggestive of pre-QCD models where quarks had unit charges, or larger. Unequivocal tests could be made with the proposed International Linear Collider, but a plasma wakefield e-e- collider could provide the most affordable option.
Last updated: 9 mars 2010, Blanchard Catherine