http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Khachatryan, V.,Sirunyan, A. M.,Tumasyan, A.,Adam, W.,Bergauer, T.,Dragicevic, M.,Erö,, J.,Fabjan, C.,Friedl, M.,Frü,hwirth, R.,Ghete, V. M.,Hartl, C.,Hö,rmann, N.,Hrubec, J.,Jeitler, M.,K Institute of Physics Pub 2015 The journal of high energy physics Vol.2015 No.1
<P>The ratio of the production cross sections times branching fractions (sigma(B-c(+/-))B(B-c(+/-) -> J/psi pi(+/-)))/(sigma(B-+/-)B(B-+/- -> J/psi K-+/-)) is studied in proton-proton collisions at a center-of-mass energy of 7TeV with the CMS detector at the LHC. The kinematic region investigated requires B-c(+/-) and B-+/- mesons with transverse momentum p(T) > 15 GeV and rapidity vertical bar y vertical bar < 1.6. The data sample corresponds to an integrated luminosity of 5.1 fb(-1). The ratio is determined to be [0.48 +/- 0.05 (stat) +/- 0.03 (syst) +/- 0.05 (tau(Bc))]%. The B-c(+/-) -> J/psi pi(+/-)pi(+/-)pi(-/+) decay is also observed in the same data sample. Using a model-independent method developed to measure the efficiency given the presence of resonant behaviour in the three-pion system, the ratio of the branching fractions B-c(+/-) -> J/psi pi(+/-)pi(+/-)pi(-/+)/B(B-c(+/-) -> J/psi pi(+/-)) is measured to be 2.55 +/- 0.80 (stat) +/- 0.33 (syst)(-0.01)(+0.04) (tau(Bc)), consistent with the previous LHCb result.</P>
Chatrchyan, S.,Khachatryan, V.,Sirunyan, A. M.,Tumasyan, A.,Adam, W.,Aguilo, E.,Bergauer, T.,Dragicevic, M.,Erö,, J.,Fabjan, C.,Friedl, M.,Frü,hwirth, R.,Ghete, V. M.,Hammer, J.,Hö,rmann, Springer-Verlag 2012 The European physical journal. C, Particles and fi Vol.72 No.12
<P>A measurement is presented of the relative prompt production rate of <I>χ</I><SUB>c2</SUB> and <I>χ</I><SUB>c1</SUB> with 4.6 fb<SUP>−1</SUP> of data collected by the CMS experiment at the LHC in pp collisions at [FORMULA OMISSION]. The two states are measured via their radiative decays <I>χ</I><SUB>c</SUB>→J/<I>ψ</I>+<I>γ</I>, with the photon converting into an e<SUP>+</SUP>e<SUP>−</SUP> pair for J/<I>ψ</I> rapidity |<I>y</I>(J/<I>ψ</I>)|<1.0 and photon transverse momentum <I>p</I><SUB>T</SUB>(<I>γ</I>)>0.5 GeV/<I>c</I>. The measurement is given for six intervals of <I>p</I><SUB>T</SUB>(J/<I>ψ</I>) between 7 and 25 GeV/<I>c</I>. The results are compared to theoretical predictions.</P>
Khachatryan, V.,Sirunyan, A. M.,Tumasyan, A.,Adam, W.,Bergauer, T.,Dragicevic, M.,Erö,, J.,Fabjan, C.,Friedl, M.,Frü,hwirth, R.,Ghete, V. M.,Hartl, C.,Hö,rmann, N.,Hrubec, J.,Jeitler, M.,K Springer Berlin Heidelberg 2015 European Physical Journal C Vol.75 No.5
<P>This paper presents a measurement of the inclusive 3-jet production differential cross section at a proton–proton centre-of-mass energy of 7 TeV using data corresponding to an integrated luminosity of 5[FORMULA OMISSION]collected with the CMS detector. The analysis is based on the three jets with the highest transverse momenta. The cross section is measured as a function of the invariant mass of the three jets in a range of 445–3270 GeV and in two bins of the maximum rapidity of the jets up to a value of 2. A comparison between the measurement and the prediction from perturbative QCD at next-to-leading order is performed. Within uncertainties, data and theory are in agreement. The sensitivity of the observable to the strong coupling constant [FORMULA OMISSION] is studied. A fit to all data points with 3-jet masses larger than 664 GeV gives a value of the strong coupling constant of [FORMULA OMISSION].</P>
Chatrchyan, S.,Khachatryan, V.,Sirunyan, A. M.,Tumasyan, A.,Adam, W.,Bergauer, T.,Dragicevic, M.,Erö,, J.,Fabjan, C.,Friedl, M.,Frü,hwirth, R.,Ghete, V. M.,Hammer, J.,Hoch, M.,Hö,rmann, N. Springer-Verlag 2012 European Physical Journal C Vol.72 No.9
<P>A measurement of the underlying event (UE) activity in proton-proton collisions at a center-of-mass energy of 7 TeV is performed using Drell-Yan events in a data sample corresponding to an integrated luminosity of 2.2 fb(-1), collected by the CMS experiment at the LHC. The activity measured in the muonic final state (q (q) over bar -> mu(+) mu(-)) is corrected to the particle level and compared with the predictions of various Monte Carlo generators and hadronization models. The dependence of the UE activity on the dimuon invariant mass is well described by PYTHIA and HERWIG++ tunes derived from the leading jet/track approach, illustrating the universality of the UE activity. The UE activity is observed to be independent of the dimuon invariant mass in the region above 40 GeV/c(2), while a slow increase is observed with increasing transverse momentum of the dimuon system. The dependence of the UE activity on the transverse momentum of the dimuon system is accurately described by MADGRAPH, which simulates multiple hard emissions.</P>
Khachatryan, V.,Sirunyan, A. M.,Tumasyan, A.,Adam, W.,Bergauer, T.,Dragicevic, M.,Erö,, J.,Fabjan, C.,Friedl, M.,Frü,hwirth, R.,Ghete, V. M.,Hartl, C.,Hö,rmann, N.,Hrubec, J.,Jeitler, M.,K Springer Berlin Heidelberg 2014 The European physical journal. C, Particles and fi Vol.74 No.9
<P>A measurement of the cross section for the production of top quark–antiquark pairs ([FORMULA OMISSION]) in association with a vector boson V (W or Z) in proton-proton collisions at [FORMULA OMISSION][FORMULA OMISSION] is presented. The results are based on a dataset corresponding to an integrated luminosity of 19.5 fb[FORMULA OMISSION] recorded with the CMS detector at the LHC. The measurement is performed in three leptonic (e and [FORMULA OMISSION]) channels: a same-sign dilepton analysis targeting [FORMULA OMISSION] events, and trilepton and four-lepton analyses designed for [FORMULA OMISSION] events. In the same-sign dilepton channel, the [FORMULA OMISSION] cross section is measured as [FORMULA OMISSION], corresponding to a significance of 1.6 standard deviations over the background-only hypothesis. Combining the trilepton and four-lepton channels, a direct measurement of the [FORMULA OMISSION] cross section, [FORMULA OMISSION], is obtained with a significance of 3.1 standard deviations. The measured cross sections are compatible with standard model predictions within their experimental uncertainties. The inclusive [FORMULA OMISSION] process is observed with a significance of 3.7 standard deviations from the combination of all three leptonic channels.</P>
Chatrchyan, S.,Khachatryan, V.,Sirunyan, A. M.,Tumasyan, A.,Adam, W.,Bergauer, T.,Dragicevic, M.,Erö,, J.,Fabjan, C.,Friedl, M.,Frü,hwirth, R.,Ghete, V. M.,Hartl, C.,Hö,rmann, N.,Hrubec, J Springer Berlin Heidelberg 2014 European Physical Journal C Vol.74 No.11
<P>A measurement of differential cross sections for the production of a pair of isolated photons in proton–proton collisions at [FORMULA OMISSION] is presented. The data sample corresponds to an integrated luminosity of 5.0[FORMULA OMISSION] collected with the CMS detector. A data-driven isolation template method is used to extract the prompt diphoton yield. The measured cross section for two isolated photons, with transverse energy above 40 and 25[FORMULA OMISSION] respectively, in the pseudorapidity range [FORMULA OMISSION], [FORMULA OMISSION] and with an angular separation [FORMULA OMISSION], is [FORMULA OMISSION][FORMULA OMISSION]. Differential cross sections are measured as a function of the diphoton invariant mass, the diphoton transverse momentum, the azimuthal angle difference between the two photons, and the cosine of the polar angle in the Collins–Soper reference frame of the diphoton system. The results are compared to theoretical predictions at leading, next-to-leading, and next-to-next-to-leading order in quantum chromodynamics.</P>
Chatrchyan, S.,Khachatryan, V.,Sirunyan, A. M.,Tumasyan, A.,Adam, W.,Bergauer, T.,Dragicevic, M.,Erö,, J.,Fabjan, C.,Friedl, M.,Frü,hwirth, R.,Ghete, V. M.,Hö,rmann, N.,Hrubec, J.,Jeitler, Springer Berlin Heidelberg 2013 The European physical journal. C, Particles and fi Vol.73 No.12
<P>Characteristics of multi-particle production in proton-proton collisions at [FORMULA OMISSION] are studied as a function of the charged-particle multiplicity, <I>N</I><SUB>ch</SUB>. The produced particles are separated into two classes: those belonging to jets and those belonging to the underlying event. Charged particles are measured with pseudorapidity |<I>η</I>|<2.4 and transverse momentum <I>p</I><SUB>T</SUB>>0.25 GeV/<I>c</I>. Jets are reconstructed from charged-particles only and required to have <I>p</I><SUB>T</SUB>>5 GeV/<I>c</I>. The distributions of jet <I>p</I><SUB>T</SUB>, average <I>p</I><SUB>T</SUB> of charged particles belonging to the underlying event or to jets, jet rates, and jet shapes are presented as functions of <I>N</I><SUB>ch</SUB> and compared to the predictions of the <SMALL>PYTHIA</SMALL> and <SMALL>HERWIG</SMALL> event generators. Predictions without multi-parton interactions fail completely to describe the <I>N</I><SUB>ch</SUB>-dependence observed in the data. For increasing <I>N</I><SUB>ch</SUB>, <SMALL>PYTHIA</SMALL> systematically predicts higher jet rates and harder <I>p</I><SUB>T</SUB> spectra than seen in the data, whereas <SMALL>HERWIG</SMALL> shows the opposite trends. At the highest multiplicity, the data–model agreement is worse for most observables, indicating the need for further tuning and/or new model ingredients.</P>
Khachatryan, V.,Sirunyan, A. M.,Tumasyan, A.,Adam, W.,Bergauer, T.,Dragicevic, M.,Erö,, J.,Fabjan, C.,Friedl, M.,Frü,hwirth, R.,Ghete, V. M.,Hartl, C.,Hö,rmann, N.,Hrubec, J.,Jeitler, M.,K Springer Berlin Heidelberg 2014 European Physical Journal C Vol.74 No.9
<P>Searches for the direct electroweak production of supersymmetric charginos, neutralinos, and sleptons in a variety of signatures with leptons and [FORMULA OMISSION], [FORMULA OMISSION], and Higgs bosons are presented. Results are based on a sample of proton-proton collision data collected at center-of-mass energy [FORMULA OMISSION] with the CMS detector in 2012, corresponding to an integrated luminosity of 19.5 [FORMULA OMISSION]. The observed event rates are in agreement with expectations from the standard model. These results probe charginos and neutralinos with masses up to 720 [FORMULA OMISSION], and sleptons up to 260 [FORMULA OMISSION], depending on the model details.</P>
Chatrchyan, S.,Khachatryan, V.,Sirunyan, A. M.,Tumasyan, A.,Adam, W.,Bergauer, T.,Dragicevic, M.,Erö,, J.,Fabjan, C.,Friedl, M.,Frü,hwirth, R.,Ghete, V. M.,Hartl, C.,Hö,rmann, N.,Hrubec, J Springer Berlin Heidelberg 2014 European Physical Journal C Vol.74 No.8
<P>Measurements are reported of the WZ and ZZ production cross sections in proton-proton collisions at [FORMULA OMISSION][FORMULA OMISSION] in final states where one Z boson decays to b-tagged jets. The other gauge boson, either W or Z, is detected through its leptonic decay (either [FORMULA OMISSION], [FORMULA OMISSION] or [FORMULA OMISSION], [FORMULA OMISSION], or [FORMULA OMISSION]). The results are based on data corresponding to an integrated luminosity of 18.9 fb[FORMULA OMISSION] collected with the CMS detector at the Large Hadron Collider. The measured cross sections, [FORMULA OMISSION] and [FORMULA OMISSION], are consistent with next-to-leading order quantum chromodynamics calculations.</P>