Leading order analysis of neutrino induced dimuon events in the CHORUS experiment

We present a leading order QCD analysis of a sample of neutrino induced charged-current events with two muons in the final state originating in the lead-scintillating fibre calorimeter of the CHORUS detector. The results are based on a sample of 8910 neutrino and 430 antineutrino induced opposite-sign dimuon events collected during the exposure of the detector to the CERN Wide Band Neutrino Beam between 1995 and 1998. % with $E_{\mu 1},E_{\mu 2} > 5$ GeV and $Q^2 > 3$ GeV$^2$ collected %between 1995 and 1998. The analysis yields a value of the charm quark mass of \mc = (1.26\pm 0.16 \pm 0.09) \GeVcc and a value of the ratio of the strange to non-strange sea in the nucleon of $\kappa = 0.33 \pm 0.05 \pm 0.05$, improving the results obtained in similar analyses by previous experiments.Comment: Submitted to Nuclear Physics

Associated Charm Production in Neutrino-Nucleus Interactions

In this paper a search for associated charm production both in neutral and charged current $\nu$-nucleus interactions is presented. The improvement of automatic scanning systems in the {CHORUS} experiment allows an efficient search to be performed in emulsion for short-lived particles. Hence a search for rare processes, like the associated charm production, becomes possible through the observation of the double charm-decay topology with a very low background. About 130,000 $\nu$ interactions located in the emulsion target have been analysed. Three events with two charm decays have been observed in the neutral-current sample with an estimated background of 0.18$\pm$0.05. The relative rate of the associated charm cross-section in deep inelastic $\nu$ interactions, $\sigma(c\bar{c}\nu)/\sigma_\mathrm{NC}^\mathrm{DIS}= (3.62^{+2.95}_{-2.42}({stat})\pm 0.54({syst}))\times 10^{-3}$ has been measured. One event with two charm decays has been observed in charged-current $\nu_\mu$ interactions with an estimated background of 0.18$\pm$0.06 and the upper limit on associated charm production in charged-current interactions at 90% C.L. has been found to be $\sigma (c\bar{c} \mu^-)/\sigma_\mathrm{CC} < 9.69 \times 10^{-4}$.Comment: 10 pages, 4 figure

Charged-Particle Multiplicities in Charged-Current Neutrino-- and Anti-Neutrino--Nucleus Interactions

The CHORUS experiment, designed to search for $\nu_{\mu}\to\nu_{\tau}$ oscillations, consists of a nuclear emulsion target and electronic detectors. In this paper, results on the production of charged particles in a small sample of charged-current neutrino-- and anti-neutrino--nucleus interactions at high energy are presented. For each event, the emission angle and the ionization features of the charged particles produced in the interaction are recorded, while the standard kinematic variables are reconstructed using the electronic detectors. The average multiplicities for charged tracks, the pseudo-rapidity distributions, the dispersion in the multiplicity of charged particles and the KNO scaling are studied in different kinematical regions. A study of quasi-elastic topologies performed for the first time in nuclear emulsions is also reported. The results are presented in a form suitable for use in the validation of Monte Carlo generators of neutrino--nucleus interactions.Comment: 17 pages, 5 figure

CMS physics technical design report : Addendum on high density QCD with heavy ions

Peer reviewe

Commissioning and performance of the CMS silicon strip tracker with cosmic ray muons

This is the Pre-print version of the Article. The official published version of the Paper can be accessed from the link below - Copyright @ 2010 IOPDuring autumn 2008, the Silicon Strip Tracker was operated with the full CMS experiment in a comprehensive test, in the presence of the 3.8 T magnetic field produced by the CMS superconducting solenoid. Cosmic ray muons were detected in the muon chambers and used to trigger the readout of all CMS sub-detectors. About 15 million events with a muon in the tracker were collected. The efficiency of hit and track reconstruction were measured to be higher than 99% and consistent with expectations from Monte Carlo simulation. This article details the commissioning and performance of the Silicon Strip Tracker with cosmic ray muons.This work is supported by FMSR (Austria); FNRS and FWO (Belgium); CNPq, CAPES, FAPERJ, and FAPESP (Brazil); MES (Bulgaria); CERN; CAS, MoST, and NSFC (China); COLCIENCIAS (Colombia); MSES (Croatia); RPF (Cyprus); Academy of Sciences and NICPB (Estonia); Academy of Finland, ME, and HIP (Finland); CEA and CNRS/IN2P3 (France); BMBF, DFG, and HGF (Germany); GSRT (Greece); OTKA and NKTH (Hungary); DAE and DST (India); IPM (Iran); SFI (Ireland); INFN (Italy); NRF (Korea); LAS (Lithuania); CINVESTAV, CONACYT, SEP, and UASLP-FAI (Mexico); PAEC (Pakistan); SCSR (Poland); FCT (Portugal); JINR (Armenia, Belarus, Georgia, Ukraine, Uzbekistan); MST and MAE (Russia); MSTDS (Serbia); MICINN and CPAN (Spain); Swiss Funding Agencies (Switzerland); NSC (Taipei); TUBITAK and TAEK (Turkey); STFC (United Kingdom); DOE and NSF (USA)

Observation of long-range, near-side angular correlations in proton-proton collisions at the LHC

This is the pre-print version of the Published Article, which can be accessed from the link below - Copyright @ 2010 Springer VerlagResults on two-particle angular correlations for charged particles emitted in proton-proton collisions at center-of-mass energies of 0.9, 2.36, and 7 TeV are presented, using data collected with the CMS detector over a broad range of pseudorapidity (eta) and azimuthal angle (phi). Short-range correlations in Delta(eta), which are studied in minimum bias events, are characterized using a simple "independent cluster" parametrization in order to quantify their strength (cluster size) and their extent in eta (cluster decay width). Long-range azimuthal correlations are studied differentially as a function of charged particle multiplicity and particle transverse momentum using a 980 inverse nb data set at 7 TeV. In high multiplicity events, a pronounced structure emerges in the two-dimensional correlation function for particle pairs with intermediate transverse momentum of 1-3 GeV/c, 2.0< |Delta(eta)| <4.8 and Delta(phi) near 0. This is the first observation of such a long-range, near-side feature in two-particle correlation functions in pp or p p-bar collisions

Observation of long-range, near-side angular correlations in proton-proton collisions at the LHC

Results on two-particle angular correlations for charged particles emitted in proton-proton collisions at center-of-mass energies of 0.9, 2.36, and 7TeV are presented, using data collected with the CMS detector over a broad range of pseudorapidity (eta) and azimuthal angle (phi). Short-range correlations in Delta(eta), which are studied in minimum bias events, are characterized using a simple "independent cluster" parametrization in order to quantify their strength (cluster size) and their extent in eta (cluster decay width). Long-range azimuthal correlations are studied differentially as a function of charged particle multiplicity and particle transverse momentum using a 980 nb(-1) data set at 7TeV. In high multiplicity events, a pronounced structure emerges in the two-dimensional correlation function for particle pairs with intermediate p(T) of 1-3 GeV/c, 2.

Measurements of D0 production and of decay branching fractions in neutrino-nucleon scattering

During the years 1994-1997, the emulsion target of the CHORUS detector was exposed to the wide-band neutrino beam of the CERN SPS of 27 GeV average neutrino energy. In total about 100 000 charged-current neutrino interactions were located in the nuclear emulsion target and fully reconstructed. From this sample of events which was based on the data acquired by new automatic scanning systems, 1048 charged-current interactions with a D0 in the final state were selected by a pattern recognition program and confirmed as neutral-particle decays through visual inspection. The ratio of decay branching fractions of the D0 into four charged particles to two charged particles was measured to be B(D0›V4)/B(D0›V2)=0.207±0.016±0.004. The inclusive measurement of the observed production rate of the D0 with a decay into four charged prongs in combination with external measurements of this topological branching ratio was used to determine the total D0 production rate by neutrinos without additional assumption on the branching fractions. The value of this rate relative to the charged-current cross-section was found to be ?(D0)/?(CC)=0.0269±0.0018±0.0013. In addition, the same normalization method was used to deduce the inclusive topological decay rate into final states with neutral particles only. A value of 0.218±0.049±0.036 was found for this branching fraction. From an observed number of three charged six-prong events the branching ratio into six charged particles was determined to be (1.2-0.9+1.3±0.2)×10-3. A measurement of the energy dependence of the D0 production by neutrinos relative to the total charged-current cross-section is also reported. This measurement was used to deduce for mc, the effective charm-quark mass, a value of (1.42±0.08)GeV/c2. © 2005 Elsevier B.V. All rights reserved.Israel Science Foundation: 328/94 CERN Grant Foundation: KRF-2003-005-C00014 Promotion and Mutual Aid Corporation for Private Schools of Japan Bundesministerium für Bildung und Forschung Instituto Nazionale di Fisica Nucleare Foundation for Fundamental Research on Matter Korean Foundation for Cancer ResearchWe gratefully acknowledge the help and support of the neutrino beam staff and of the numerous technical collaborators who contributed to the detector construction, operation, emulsion pouring, development, and scanning. The experiment was made possible by grants from the Institut Interuniversitaire des Sciences Nucléaires and the Interuniversitair Instituut voor Kernwetenschappen (Belgium), the Israel Science Foundation (grant 328/94) and the Technion Vice President Fund for the Promotion of Research (Israel), CERN (Geneva, Switzerland), the German Bundesministerium für Bildung und Forschung (Germany), the Institute of Theoretical and Experimental Physics (Moscow, Russia), the Istituto Nazionale di Fisica Nucleare (Italy), the Promotion and Mutual Aid Corporation for Private Schools of Japan and Japan Society for the Promotion of Science (Japan), the Korea Research Foundation Grant (KRF-2003-005-C00014) (Republic of Korea), the Foundation for Fundamental Research on Matter FOM and the National Scientific Research Organization NWO (The Netherlands), and the Scientific and Technical Research Council of Turkey (Turkey). We gratefully acknowledge their support

Measurement of charm production in antineutrino charged-current interactions

During the years 1994-1997, the emulsion target of the CHORUS detector was exposed to the wide-band neutrino beam of the CERN SPS collecting about 10 6 neutrino interactions. A measurement of ?¯µ-induced charm production is performed by using the presence of a 5% ?¯µ component in the ?µ beam. The measurement takes advantage of the capability to observe the decay topology in the emulsion. The analysis is based on a sample of charged-current interactions with at least one identified muon. About 100000 were located in the emulsion target and fully reconstructed. By requiring a positive muon charge as determined by the CHORUS muon spectrometer, 32?¯µ-induced charm events were observed with an estimated background of 3.2 events. At an average antineutrino energy in the neutrino beam of 18 GeV, the charm production rate induced by antineutrinos is measured to be ?(?¯µN›µ+c¯X)/?(?¯µN›µ+X) =(5.0-0.9+1.4(stat)±0.7(syst))%. The ratio between neutral and charged charm production rates in this process is (2.6-1.0+1.7(stat)±0.8(syst)). The charm production rate as a function of the antineutrino energy is found to be in good agreement with previous results derived from di-lepton data. © 2004 Elsevier B.V. All rights reserved.Bundesministerium für Bildung und Forschung Promotion and Mutual Aid Corporation for Private Schools of Japan Grant Foundation: KRF-2003-005-C00014 Israel Science Foundation: 328/94 CERN Brussels Instituut voor Milieubeheer Instituto Nazionale di Fisica Nucleare Foundation for Fundamental Research on Matter Korean Foundation for Cancer ResearchWe gratefully acknowledge the help and support of the neutrino-beam staff and of the numerous technical collaborators who contributed to the detector construction, operation, emulsion pouring, development, and scanning. The experiment was made possible by grants from the Institut Interuniversitaire des Sciences Nucléaires and the Interuniversitair Instituut voor Kernwetenschappen (Belgium); the Israel Science Foundation (Grant 328/94) and the Technion Vice President Fund for the Promotion of Research (Israel); CERN (Geneva, Switzerland); the German Bundesministerium für Bildung und Forschung (Germany); the Institute of Theoretical and Experimental Physics (Moscow, Russia); the Istituto Nazionale di Fisica Nucleare (Italy); the Promotion and Mutual Aid Corporation for Private Schools of Japan and Japan Society for the Promotion of Science (Japan); Korea Research Foundation Grant (KRF-2003-005-C00014) (Republic of Korea); the Foundation for Fundamental Research on Matter FOM and the National Scientific Research Organization NWO (The Netherlands); and the Scientific, and Technical Research Council of Turkey (Turkey). We gratefully acknowledge their support