123930049
Heavy Quark Production at CMS and ATLAS
measured with the new data against the framework of quantum chromodynamics (QCD). Two general-purpose detectors, ATLAS [1] and CMS [2], designed to explore the physics at the TeV scale, have an extensive research program for heavy-flavour studies. The two experiments are very different in the layout chosen for the magnet system. In ATLAS, a solenoid provides the magnetic ﬁeld for the Inner Tracker, while a system of air-core toroids outside the calorimeters provides the ﬁeld for the Muon Spectrometer. The magnetic ﬁeld in CMS is provided by a single very large solenoid which contains both the Inner Tracker and the calorimeters. The muon chambers are embedded in the iron of the solenoid return yoke. The magnet layout determines the weight (ATLAS is larger but lighter) of the two detectors. The potential of ATLAS and CMS for heavy-flavour measurements is presented for the LHC start-up luminosities (10 pb
118619470
Prospects for B Physics Measurements using the CMS Detector at the LHC
The LHC provides new opportunities to improve our understanding of the b quark using high statistics data samples and the 14 TeV center-of-mass energy. The prospects to measure the cross section for inclusive b production in events containing jets and at least one muon are presented. Additionally, the feasibility for CMS to measure the mass and the lifetime of the BBc meson and to search for the rare leptonic decay BsB →μμ are presented. Detailed studies of detector systematic effects and theoretical uncertainties are included Presented at XXXIII International Conference on High Energy Physics (ICHEP) July 26 August 2, 2006 Moscow
204171619
Total two photon hadronic cross-section and charm production cross-section measurement with the L3 detector
29354690
The CMS Magnetic Field Map Performance
The Compact Muon Solenoid (CMS) is a general-purpose detector designed to run at the highest luminosity at the CERN Large Hadron Collider (LHC). Its distinctive features include a 4 T superconducting solenoid with 6 m diameter by 12.5 m long free bore, enclosed inside a 10000-ton return yoke made of construction steel. Accurate characterization of the magnetic field everywhere in the CMS detector is required. During two major tests of the CMS magnet the magnetic flux density was measured inside the coil in a cylinder of 3.448 m diameter and 7 m length with a specially designed field-mapping pneumatic machine as well as in 140 discrete regions of the CMS yoke with NMR probes, 3-D Hall sensors and flux-loops. A TOSCA 3-D model of the CMS magnet has been developed to describe the magnetic field everywhere outside the tracking volume measured with the field-mapping machine. A volume based representation of the magnetic field is used to provide the CMS simulation and reconstruction software with the magnetic field values. The value of the field at a given point of a volume is obtained by interpolation from a regular grid of values resulting from a TOSCA calculation or, when available, from a parameterization. The results of the measurements and calculations are presented, compared and discussed.
21384151
Aligning the CMS muon endcap detector with a system of optical sensors
The positions and orientations of one sixth of 468 large cathode strip chambers in the endcaps of the CMS muon detector are directly monitored by several hundred sensors including 2-D optical sensors with linear CCDs illuminated by cross-hair lasers. Position measurements obtained by photo- grammetry and survey under field-off conditions show that chambers in the +Z endcap have been placed on the yoke disks with an average accuracy of about plusmn1 mm in all 3 dimensions. We reconstruct absolute Zciws-positions and orientations of chambers at B=0T and B=4T using data from the optical alignment system. The measured position resolution and sensitivity to relative motion is ~60 mum. The precision for measuring chamber positions taking into account mechanical tolerances is ~270 mum. Comparing reconstruction of optical alignment data and photogrammetry measurements at B=0T indicates an accuracy of ~ 680 mum currently achieved with the hardware alignment system. Optical position measurements at B=4T show significant chamber displacements of up to 13 mm due to yoke disk deformation.
117234080
B production at the LHC / QCD aspects
The LHC provides new opportunities to improve our understanding of the b quark using high statistics data samples and the 14 TeV center-of-mass energy. The prospects to measure the cross section for inclusive b production in events containing jets and at least one muon are presented. Studies of detector systematic effects and theoretical uncertainties are included. QCD aspects of the beauty production are discussed.
121193004
Study of nuclear medium effects on polarization in (p, 2p) scattering at 1 GeV
We report on experimental investigation of the (p, 2p) reactions on nuclei 6Li, 7Li, 12C and 40Ca. In this experiment, polarizations of the secondary protons from the (p, 2p) reactions are measured using 1 GeV proton beam of the PNPI synchrocyclotron. Two final protons from the reaction are detected in coincidence by means of a two-arm magnetic spectrometer at non-symmetric scattering angles. The resolution of the spectrometer on separation energy of 4.5 MeV (FWHM) is enough to distinguish reliably the shell structure of the investigated nuclei. In order to measure polarization of the two secondary protons, both spectrometer arms are equipped with multiwire proportional chamber polarimeters.Strong reduction of polarizations (large depolarization factor) relatively to free pp scattering is observed in the experiment. The 6Li, 7Li P-shell data are interpreted in terms of this reduction being combined with classical phenomenon of the effective polarization calculated with the help of DWIA.For the S-shell protons the depolarization factors are apparently seen not being obscured by the spin-orbit coupling. In case of the 7Li S-shell data the depolarization factors calculated by deviation from IA are found to be ΔP/P=0.31±0.07 and 0.39±0.04 for the scattered and recoil proton polarization, respectively. As estimations show, significant and roughly equal polarization reduction of the two secondary protons with essentially different energies (≈-200 and 800 MeV) can hardly be explained by a trivial nuclear distortion effect like depolarization due to rescatterings in nuclear matter. Measurements with heavier nucleus targets (12C, 40Ca) show that magnitude of the depolarization is a decreasing function of the nuclear density in the part of the nucleus volume which effectively contributes to the pp scattering in a nucleus. An explanation of the observed depolarization might be done in terms of modification of the pp-scattering amplitude in the nuclear meidum.
125946313
SPATIAL FOCUSING OF 1-GeV PROTONS BY A BENT MONOCRYSTAL
53583095
High Precision Measurements of the Pion Proton Differential Cross Section
Study of the elastic scattering can produce a rich information on the dynamics of the strong interaction. The EPECUR collaboration is aimed at the research of baryon resonances in the second resonance region via pion-proton elastic scattering and kaon-lambda production. The experiment features high statistics and better than 1 MeV resolution in the invariant mass thus allowing searches for narrow resonances with the coupling to the pi p channel as low as 5%. The experiment is of "formation" type, i.e. the resonances are produced in s-channel and the scan over the invariant mass is done by the variation of the incident pion momentum which is measured with the accuracy of 0.1% with a set of 1 mm pitch proportional chambers located in the first focus of the beam line. The reaction is identified by a magnetless spectrometer based on wire drift chambers with a hexagonal structure. Background suppression in this case depends on the angular resolution, so the amount of matter in the chambers and the setup was minimized to reduce multiple scattering. 
The measurements started in 2009 with the setup optimized for elastic pion-proton scattering. With 3 billions of triggers already recorded the differential cross section of the elastic pi p-scattering on a liquid hydrogen target in the region of the diffraction minimum is measured with statistical accuracy about 1% in 1 MeV steps in terms of the invariant mass. The paper covers the experimental setup, current status and some preliminary results.
125792222
THE ELECTRON TRANSITION RADIATION DETECTOR IN THE EXPERIMENT TO MEASURE THE ASYMMETRY IN THE BETA DECAY OF POLARIZED SIGMA- HYPERONS