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Past seminars year 2007-2008 |
| 12thOct. 2007 |
Central exclusive dijets at hadron colliders
| talk in pdf
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| 14:30 |
Dr. Igor Ivanov (ULg) |
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Abstract:
There is much interest in the production of a hard system in a
pomeron-pomeron collision at hadronic colliders, especially, central
exclusive Higgs production. Theoretical calculation of such a reaction
contains several steps. It has been suggested that central exclusive
dijet
production, for which Tevatron now has data, can provide a useful check
of
the accuracy of theoretical calculations. Here we discuss the current
status of dijet production and its relation with Higgs production.
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| 23stNov. 2007 |
Observation of D0 oscillation at B-factories
| talk in pdf
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| 14:30 |
Prof. Gianluca Cavoto (INFN - Roma La Sapienza) |
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Abstract:
The neutral charm meson (the D0) meson is expected to undergo quantum
mechanical "mixing" with its own antiparticle like the neutral strange and
bottom mesons (K0 and B0). However, mixing in the D0 system is very suppressed
due to the GIM mechanism. Over the past several decades, many experiments have
searched for signatures of mixing in the D0 system. I will present the latest
results of the B-factory BaBar and Belle that show evidence for D0-D0bar
mixing in different channels. These measurements of charm-meson mixing provide
a new probe of the Standard Model of particle physics.
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| 18thFeb. 2008 |
New tools in jet physics: SISCone (a new cone algorithm) and
jet areas (a new concept)
| talk in pdf
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| 14:30 |
Gregory Soyez (ULg/BNL) |
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Abstract:
As an introduction, I will introduce the concept of jets and the ambiguity in
their definition. Then I will concentrate on one class of jet definitions:
the cone algorithms. I will explain how they work, what they should satisfy
and how previous implementations fail to satisfy those requirements. I will
describe SISCone as a solution to those failures and expose its behaviours
such as speed and comparison with previous cone algorithms. In the last part
of the talk, I will put a definition on the concept of jet areas and
investigate its basic properties and its applications to soft background
suppression.
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| 4thApril 2008 |
The low energy side of IceCube
| talk in pdf
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| 14:30 |
Andreas Gross (Max Planck Inst. - Heidelberg) |
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Abstract:
The IceCube observatory at the geographic South Pole is the largest
operating neutrino telescope worldwide. Its main purpose is the detection
of neutrinos from extragalcatic sources at energies above a few TeV. The
status of IceCube will be summarized.
The focus of this talk will be on lower energies, i.e. 10 GeV up to a few
TeV. The motivation to consider these energies comes from the potential to
detect Galactic point sources and WIMPs and from the measurement of
neutrino oscillations at energies above 10 GeV. Since IceCube was designed
for higher energies, its performance is not optimum at these energies. The
concept of a nested array embedded in the IceCube detector provides an
efficient way to achieve a significantly improved performance. Currently,
the AMANDA detector integrated in Icecube is used as a low energy core.
The effect on the low energy performance is shown on the example of
Galactic point sources. For logistic and for physics reasons, it was
decided to replace AMANDA by a dedicated low energy core, the IceCube Deep
Core. With it's location centered in IceCube and much deeper in the ice
than AMANDA, it will be possible to identify starting neutrino induced
tracks and efficiently veto the atmospheric muon background. With this
active veto, IceCube will become a 4 Pi neutrino detector.
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| 24thApril 2008 |
DAQ system upgrade of the BESIII experiment at the BEPCII e+e- collider
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| 14:30 |
Yang YiFan (Institute of High Energy Physics, CAS, Beijing) |
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Abstract:
Standard bus systems are commonly used in modern particle physics
experiments, as the bridge of the front electronics system and the online
data process system. The data readout speed is one of the most important
indexes of the DAQ system. This talk will give an introduction to the
common used bus systems and data transfer interfaces in modern particle physics
experiments at first. After that, based on the analysis of the current DAQ
system of the BESIII experiment at the BEPCII e+e- collider in China, the talk
points out the possible limit of the current
DAQ system when it faces the new system requirements. At last, the talk
bring up a new readout method based on 2eVME protocol which integrated the
advantages of two popular readout architecture used frequently now. The
implementation of the new readout circuit will be introduced as well as a
simple introduction to the BESIII architecture.
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| 9thMay 2008 |
Search for New Physics in Electron-Positron Events at CDF
| talk in pdf
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| 14:30 |
Sam Harper (Oxford University) |
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Abstract:
I will present a model independent search for new physics producing a
narrow resonance in the electron-positron mass spectrum resulting from 1.96 TeV
ppbar events recorded by the CDF II detector at the Fermilab Tevatron. This
channel is of particular interest as it is a golden channel for the discovery
of new physics models such as Warped Extra Dimensions and various GUT models at
the LHC and could boast a new physics discovery as earily as next year. The
analysis will be presented from a perspective on how the techniques and methods
used can be applied to the LHC as the Tevatron and LHC share many common
experimental challenges. Finally, I will present the resulting exclusion limits
on the Randall-Sundrum graviton and the E6 Z's with some discussion on what
this means for the LHC.
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| 23thMay 2008 |
The Beijing Spectrometer III Experiment - Status and Physics Program
| talk in pdf
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| 14:30 |
Niklaus Berger (IHEP, Beijing) |
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Abstract:
The new Beijing Electron-Positron Collider BEPC II will provide
unprecedented luminosities at charm-tau energies. The Beijing Spectrometer
III (BES III) experiment was designed to make the best possible use of the
large statistics provided. The experiment has recently been moved to the
interaction region and commissioning with beam will start next month.
In my talk I will present the detector and discuss the BES III physics
program.
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| 6thJune 2008 |
Search for new physics in top pair mass spectrum distributions at CMS
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| 14:30 |
Eric Chabert (IPNL, Lyon, France) |
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Abstract:
CMS is one of two generalist-omni-purpose experiments installed at the
LHC, where two proton beams will collide at a 14 TeV center of mass energy.
The beginning of the data taking is scheduled in 2008. The physics
program at the LHC aims to find signals of physics beyond the standard
model and give answers for understanding the mechanism of electroweak
symmetry breaking.
Top physics will play a leading role in both of these aspects. Many BSM
models predict resonances decaying into top quark pair. These resonances
can be searched in the differential distributions of the top pairs. A
top pair invariant mass analysis in the semi-leptonic channel will be
presented. Systematic errors and sensitivity to new physic will be
discussed.
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| 28thJuly 2008 |
Detecting neutrinos from Gamma-Ray Bursts with IceCube
| talk in html
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| 14:30 |
Dr. Garmt de Vries-Uiterweerd (Universiteit Utrecht) |
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Abstract:
Neutrino astronomy is an emerging field of science that will open up a
completely new view of the universe. Since neutrinos only undergo weak
interactions, they can cross enormous distances without being absorbed or
deflected. This makes them a powerful tool to study the deep cosmos, but large
detectors are needed in order to detect cosmic neutrinos, precisely because
they interact so weakly.
The IceCube neutrino observatory is currently under construction at the South
Pole. At the moment, half of the planned detector is complete. IceCube
currently consists of 40 fully operational strings, deployed in 0.5 km3 of ice
and carrying 60 sensitive photomultipliers (light detectors) each. These
instruments detect the light produced by interactions of neutrinos underneath
the ice. From the observed arrival times of the light at each of the
photomultipliers, one can reconstruct the direction of the original neutrino,
and hence the position of its source on the sky.
The data collected by IceCube can be used to study the production of high
energy neutrinos in Gamma-Ray Bursts (GRBs), powerful explosions at
cosmological distances. Many details about this phenomenon remain unknown. The
detection of neutrinos from GRBs would be a major discovery, but also
non-detection would provide valuable insights on the mechanisms powering a GRB.
Since the expected number of detected neutrinos from each GRB is very small and
possibly not distinguishable from the background, a method is needed to combine
the data from a large number of GRBs. One such method is the so-called stacking
of time profiles. In my presentation, I will outline this method and several
issues related to this analysis.
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Past seminars in:
[2003-2004]
[2004-2005]
[2005-2006]
[2006-2007]
[2007-2008]
[2008-2009]
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