Publications (760)3513.63 Total impact
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ABSTRACT: A measurement is presented of differential cross sections for Higgs boson (H) production in pp collisions at \(\sqrt{s}=8\) \(\,\text {TeV}\). The analysis exploits the \({H} \rightarrow {\gamma }{\gamma }\) decay in data corresponding to an integrated luminosity of 19.7\(\,\text {fb}^\text {1}\) collected by the CMS experiment at the LHC. The cross section is measured as a function of the kinematic properties of the diphoton system and of the associated jets. Results corrected for detector effects are compared with predictions at nexttoleading order and nexttonexttoleading order in perturbative quantum chromodynamics, as well as with predictions beyond the standard model. For isolated photons with pseudorapidities \(\eta <2.5\), and with the photon of largest and nexttolargest transverse momentum (\(p_{\mathrm {T}} ^{\gamma }\)) divided by the diphoton mass \(m_{\gamma \gamma }\) satisfying the respective conditions of \(p_{\mathrm {T}} ^{\gamma }/m_{\gamma \gamma }> 1/3\) and \({>}1/4\), the total fiducial cross section is \(32 \pm 10\) \(\text {\,fb}\).  [Show abstract] [Hide abstract]
ABSTRACT: The perevent yield of the highest transverse momentum charged particle and chargedparticle jet, integrated above a given p[min over T] threshold starting at p[min over T] = 0.8 and 1 GeV, respectively, is studied in pp collisions at √s = 8 TeV. The particles and the jets are measured in the pseudorapidity ranges η < 2.4 and 1.9, respectively. The data are sensitive to the momentum scale at which parton densities saturate in the proton, to multiple partonic interactions, and to other key aspects of the transition between the soft and hard QCD regimes in hadronic collisions.  [Show abstract] [Hide abstract]
ABSTRACT: Measurements of the \(\mathrm{Z}\) \(\mathrm{Z}\) production cross sections in proton–proton collisions at centerofmass energies of 7 and 8\(~\mathrm{TeV}\) are presented. Candidate events for the leptonic decay mode \(\mathrm{Z}\mathrm{Z}\rightarrow 2\mathrm{l} 2\nu \), where \(\mathrm{l}\) denotes an electron or a muon, are reconstructed and selected from data corresponding to an integrated luminosity of 5.1 (19.6)\(\,\text {fb}^\text {1}\) at 7 (8)\(~\mathrm{TeV}\) collected with the CMS experiment. The measured cross sections, \(\sigma (\mathrm {p}\mathrm {p}\rightarrow \mathrm{Z}\mathrm{Z}) = 5.1_{1.4}^{+1.5}\,\text {(stat)} \,_{1.1}^{+1.4}\,\text {(syst)} \pm 0.1\,\text {(lumi)} \text {~pb} \) at 7\(~\mathrm{TeV}\), and \(7.2_{0.8}^{+0.8}\,\text {(stat)} \,_{1.5}^{+1.9}\,\text {(syst)} \,\pm \, 0.2\,\text {(lumi)} \text {~pb} \) at 8\(~\mathrm{TeV}\), are in good agreement with the standard model predictions with nexttoleadingorder accuracy. The selected data are analyzed to search for anomalous triple gauge couplings involving the \(\mathrm{Z}\) \(\mathrm{Z}\) final state. In the absence of any deviation from the standard model predictions, limits are set on the relevant parameters. These limits are then combined with the previously published CMS results for \(\mathrm{Z}\) \(\mathrm{Z}\) in 4\(\mathrm{l}\) final states, yielding the most stringent constraints on the anomalous couplings.  [Show abstract] [Hide abstract]
ABSTRACT: A search for neutral Higgs bosons decaying into a \( \mathrm{b}\overline{\mathrm{b}} \) quark pair and produced in association with at least one additional b quark is presented. This signature is sensitive to the Higgs sector of the minimal supersymmetric standard model (MSSM) with large values of the parameter tan β. The analysis is based on data from protonproton collisions at a centerofmass energy of 8 TeV collected with the CMS detector at the LHC, corresponding to an integrated luminosity of 19.7 fb−1. The results are combined with a previous analysis based on 7 TeV data. No signal is observed. Stringent upper limits on the cross section times branching fraction are derived for Higgs bosons with masses up to 900 GeV, and the results are interpreted within different MSSM benchmark scenarios, m hmax, m hmod +, m hmod −, lightstau and lightstop. Observed 95% confidence level upper limits on tan β, ranging from 14 to 50, are obtained in the m hmod + benchmark scenario. 
Article: Search for a Higgs boson in the mass range from 145 to 1000 GeV decaying to a pair of W or Z bosons
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ABSTRACT: A search for a heavy Higgs boson in the H → WW and H → ZZ decay channels is reported. The search is based upon protonproton collision data samples corresponding to an integrated luminosity of up to 5.1 fb−1 at \( \sqrt{s}=7 \) TeV and up to 19.7fb−1 at \( \sqrt{s}=8 \) TeV, recorded by the CMS experiment at the CERN LHC. Several final states of the H → WW and H → ZZ decays are analyzed. The combined upper limit at the 95% confidence level on the product of the cross section and branching fraction exclude a Higgs boson with standard modellike couplings and decays in the range 145 < m H < 1000 GeV. We also interpret the results in the context of an electroweak singlet extension of the standard model.  [Show abstract] [Hide abstract]
ABSTRACT: A comparison of the differential cross sections for the processes Z/γ * + jets and photon (γ)+jets is presented. The measurements are based on data collected with the CMS detector at \( \sqrt{s}=8 \) TeV corresponding to an integrated luminosity of 19.7 fb−1. The differential cross sections and their ratios are presented as functions of p T. The measurements are also shown as functions of the jet multiplicity. Differential cross sections are obtained as functions of the ratio of the Z/γ *p T to the sum of all jet transverse momenta and of the ratio of the Z/γ *p T to the leading jet transverse momentum. The data are corrected for detector effects and are compared to simulations based on several QCD calculations.  [Show abstract] [Hide abstract]
ABSTRACT: The e[superscript +]e[superscript ] → K[superscript +]K[superscript ] cross section and chargedkaon electromagnetic form factor are measured in the e[superscript +]e[superscript ] centerofmass energy range (E) from 2.6 to 8.0 GeV using the initialstate radiation technique with an undetected photon. The study is performed using 469 fb[superscript 1] of data collected with the BABAR detector at the PEPII2 e[superscript +]e[superscript ] collider at centerofmass energies near 10.6 GeV. The form factor is found to decrease with energy faster than 1/E[superscript 2] and approaches the asymptotic QCD prediction. Production of the K[superscript +]K[superscript ] final state through the J/ψ and ψ(2S) intermediate states is observed. The results for the kaon form factor are used together with data from other experiments to perform a modelindependent determination of the relative phases between electromagnetic (singlephoton) and strong amplitudes in J/ψ and ψ(2S) → K[superscript +]K[superscript ] decays. The values of the branching fractions measured in the reaction e[superscript +]e[superscript ] → K[superscript +]K[superscript ] are shifted relative to their true values due to interference between resonant and nonresonant amplitudes. The values of these shifts are determined to be about ±5% for the J/ψ meson and ±15% for the ψ(2S) meson.  [Show abstract] [Hide abstract]
ABSTRACT: The doubledifferential cross sections of promptly produced J/ψ and ψ(2S) mesons are measured in pp collisions at sqrt[s]=7 TeV, as a function of transverse momentum p_{T} and absolute rapidity y. The analysis uses J/ψ and ψ(2S) dimuon samples collected by the CMS experiment, corresponding to integrated luminosities of 4.55 and 4.90 fb^{1}, respectively. The results are based on a twodimensional analysis of the dimuon invariant mass and decay length, and extend to p_{T}=120 and 100 GeV for the J/ψ and ψ(2S), respectively, when integrated over the interval y<1.2. The ratio of the ψ(2S) to J/ψ cross sections is also reported for y<1.2, over the range 10<p_{T}<100 GeV. These are the highest p_{T} values for which the cross sections and ratio have been measured.  [Show abstract] [Hide abstract]
ABSTRACT: A measurement of the Higgs boson mass is presented based on the combined data samples of the ATLAS and CMS experiments at the CERN LHC in the H→γγ and H→ZZ→4ℓ decay channels. The results are obtained from a simultaneous fit to the reconstructed invariant mass peaks in the two channels and for the two experiments. The measured masses from the individual channels and the two experiments are found to be consistent among themselves. The combined measured mass of the Higgs boson is m_H=125.09±0.21 (stat)±0.11 (syst) GeV.  [Show abstract] [Hide abstract]
ABSTRACT: We report a measurement of the timedependent CP asymmetry of [bar over B][superscript 0] → D[(*) over CP]h[superscript 0] decays, where the light neutral hadron h[superscript 0] is a π[superscript 0], η, or ω meson, and the neutral D meson is reconstructed in the CP eigenstates K[superscript +]K[superscript ], K[0 over S]π[superscript 0], or K[0 over S]ω. The measurement is performed combining the final data samples collected at the ϒ(4S) resonance by the BABAR and Belle experiments at the asymmetricenergy B factories PEPII at SLAC and KEKB at KEK, respectively. The data samples contain (471 ± 3) × 10[superscript 6] B[bar over B] pairs recorded by the BABAR detector and (772 ± 11) × 10[superscript 6] B[bar over B] pairs recorded by the Belle detector. We measure the CP asymmetry parameters η[subscript f]S = +0.66 ± 0.10(stat) ± 0.06(syst) and C = 0.02 ± 0.07(stat) ± 0.03(syst). These results correspond to the first observation of CP violation in [bar over B][superscript 0] → D[(*) over CP]h[superscript 0] decays. The hypothesis of no mixinginduced CP violation is excluded in these decays at the level of 5.4 standard deviations.  [Show abstract] [Hide abstract]
ABSTRACT: A search is presented for the decay ϒ(1S)→γA[superscript 0], A[superscript 0] → c[bar over c], where A[superscript 0] is a candidate for the CPodd Higgs boson of the nexttominimal supersymmetric standard model. The search is based on data collected with the BABAR detector at the ϒ(2S) resonance. A sample of ϒ(1S) mesons is selected via the decay ϒ(2S) → π[superscript +]π[superscript ]ϒ(1S). The A[superscript 0] → c[bar over c] decay is identified through the reconstruction of hadronic D[superscript 0], D[superscript +], and D[superscript *](2010)[superscript +] meson decays. No significant signal is observed. The measured 90% confidencelevel upper limits on the product branching fraction B(ϒ(1S) → γA[superscript 0]) × B(A[superscript 0] → c[bar over c]) range from 7.4 × 10[superscript 5] to 2.4 × 10[superscript 3] for A[superscript 0] masses from 4.00 to 8.95 GeV/c[superscript 2] and 9.10 to 9.25 GeV/c[superscript 2], where the region between 8.95 and 9.10 GeV/c[superscript 2] is excluded because of background from ϒ(2S) → γχ[subscript bJ](1P), χ[subscript bJ](1P) → γϒ(1S) decays.  [Show abstract] [Hide abstract]
ABSTRACT: We perform a measurement of the τ → lγν[bar over ν] (l = e,μ) branching fractions for a minimum photon energy of 10 MeV in the τ rest frame, using 431 fb[superscript 1] of e[superscript +]e[superscript ] collisions collected at the centerofmass energy of the ϒ(4S) resonance with the BABAR detector at the PEPII storage rings. We find B(τ → μγν[bar over ν]) = (3.69 ± 0.03 ± 0.10) × 10[superscript 3] and B(τ → eγν[bar over ν]) = (1.847 ± 0.015 ± 0.052) × 10[superscript 2], where the first quoted error is statistical and the second is systematic. These results are substantially more precise than previous measurements.  [Show abstract] [Hide abstract]
ABSTRACT: Based on a sample of 500 million e[superscript +]e[superscript ] → c[bar over c] events recorded by the BABAR detector at c.m. energies of close to 10.6 GeV, we report on a study of the decay D[superscript 0] → π[superscript ]e[superscript +]ν[subscript e]. We measure the ratio of branching fractions, R[subscript D] = B(D[superscript 0] → π[superscript ]e[superscript +]ν[subscript e])/B(D[superscript 0] → K[superscript ]π[superscript +]) = 0.0713 ± 0.0017[subscript stat] ± 0.0024[subscript syst], and use the present world average for B(D[superscript 0] → K[superscript ]π[superscript +] to obtain B(D[superscript 0] → π[superscript ]e[superscript +]ν[subscript e]) = (2.770 ± 0.068[subscript stat] ± 0.092[subscript syst] ± 0.037[subscript ext]) × 10[superscript 3] where the third error accounts for the uncertainty on the branching fraction for the reference channel. The measured dependence of the differential branching fraction on q[superscript 2], the fourmomentum transfer squared between the D and the π meson, is compared to various theoretical predictions for the hadronic form factor, f[π over +,D](q[superscript 2]), and the normalization V[subscript cd] × f[π over +,D](q[superscript 2] = 0) = 0.1374 ± 0.0038[subscript stat] ± 0.0022[subscript syst] ± 0.0009[subscript ext] is extracted from a fit to data. Using the most recent LQCD prediction of f[π over +,D](q[superscript 2] = 0) = 0.666 ± 0.029, we obtain V[subscript cd] = 0.206 ± 0.007[subscript exp] ± 0.009[subscript LQCD]. Assuming, instead, V[subscript cd] = V[subscript us] = 0.2252 ± 0.0009, we obtain f[π over +,D](q[superscript 2] = 0) = 0.610 ± 0.020subscript exp] ± 0.005[subscript ext]. The q[superscript 2] dependence of f[π over +,D](q[superscript 2]) is compared to a variety of multipole parametrizations. This information is applied to B[superscript 0] → π[superscript ]e[superscript +]ν[subscript e] decays and, combined with an earlier B[superscript 0] → π[superscript ]e[superscript +]ν[subscript e] measurement by BABAR, is used to derive estimates of V[subscript ub].  [Show abstract] [Hide abstract]
ABSTRACT: We present Dalitz plot analyses for the decays of B mesons to D[superscript −]D[superscript 0]K[superscript +] and [bar over D][superscript 0]D[superscript 0]K[superscript +]. We report the observation of the D[* over s1](2700)[superscript +] resonance in these two channels and obtain measurements of the mass M(D[* over s1](2700)[superscript +]) = 2699[+14 over −7] MeV/c[superscript 2] and of the width Γ(D[* over s1](2700)[superscript +]) = 127[+24 over −19] MeV, including statistical and systematic uncertainties. In addition, we observe an enhancement in the D[superscript 0]K[superscript +] invariant mass around 2350–2500 MeV/c[superscript 2] in both decays B[superscript 0] → D[superscript −]D[superscript 0]K[superscript +] and B[superscript +] → [bar over D][superscript 0]D[superscript 0]K[superscript +], which we are not able to interpret. The results are based on 429 fb[superscript −1] of data containing 471×10[superscript 6]B[bar over B] pairs collected at the ϒ(4S) resonance with the BABAR detector at the SLAC National Accelerator Laboratory.  [Show abstract] [Hide abstract]
ABSTRACT: A systematic study of the factorization of longrange azimuthal twoparticle correlations into a product of singleparticle anisotropies is presented as a function of p[subscript T] and η of both particles and as a function of the particle multiplicity in PbPb and pPb collisions. The data were taken with the CMS detector for PbPb collisions at √[s[subscript NN] = 2.76 TeV and pPb collisions at √s[subscript NN] = 5.02 TeV, covering a very wide range of multiplicity. Factorization is observed to be broken as a function of both particle p[subscript T] and η. When measured with particles of different p[subscript T], the magnitude of the factorization breakdown for the second Fourier harmonic reaches 20% for very central PbPb collisions but decreases rapidly as the multiplicity decreases. The data are consistent with viscous hydrodynamic predictions, which suggest that the effect of factorization breaking is mainly sensitive to the initialstate conditions rather than to the transport properties (e.g., shear viscosity) of the medium. The factorization breakdown is also computed with particles of different η. The effect is found to be weakest for midcentral PbPb events but becomes larger for more central or peripheral PbPb collisions, and also for veryhighmultiplicity pPb collisions. The ηdependent factorization data provide new insights to the longitudinal evolution of the medium formed in heavy ion collisions.  [Show abstract] [Hide abstract]
ABSTRACT: We present a measurement of the asymmetry A[subscript CP] between samesign inclusive dilepton samples ℓ[superscript +]ℓ[superscript +] and ℓ[superscript −]ℓ[superscript −] (ℓ=e, μ) from semileptonic B decays in Υ(4S)→B[bar over B] events, using the complete data set recorded by the BABAR experiment near the Υ(4S) resonance, corresponding to 471×10[superscript 6] B[bar over B] pairs. The asymmetry A[subscript CP] allows comparison between the mixing probabilities P([bar over B][superscript 0]→B[superscript 0]) and P(B[superscript 0]→[bar over B][superscript 0]), and therefore probes CP and T violation. The result, A[subscript CP]=[−3.9±3.5(stat)±1.9(syst)]×10[superscript −3], is consistent with the standard model expectation.  [Show abstract] [Hide abstract]
ABSTRACT: We report the observation of the baryonic decay [bar over B][superscript 0 → Λ[+ over c][bar over p]K[superscript ]K[superscript +] using a data sample of 471 × 10[superscript 6] B[bar over B] pairs produced in e[superscript +]e[superscript ] annihilations at √s = 10.58 GeV. This data sample was recorded with the BABAR detector at the PEPII storage ring at SLAC. We find B([bar over B][superscript 0 → Λ[+ over c][bar over p]K[superscript ]K[superscript +]) = (2.5 ± 0.4[subscript (stat)] ± 0.2[subscript (syst)] ± 0.6[subscript B(Λ[+ over c])) × 10[superscript 5], where the uncertainties are statistical, systematic, and due to the uncertainty of the Λ[+ over c] → pK[superscript ]π[superscript +] branching fraction, respectively. The result has a significance corresponding to 5.0 standard deviations, including all uncertainties. For the resonant decay [bar over B][superscript 0] → Λ[+ over c][bar over p]ϕ, we determine the upper limit B([bar over B][superscript 0] → Λ[+ over c][bar over p]ϕ) < 1.2 × 10[superscript 5] at 90% confidence level. 
Article: Search for new π[superscript 0]like particles produced in association with a τlepton pair
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ABSTRACT: We report on a search in e[superscript +]e[superscript ] annihilations for new π[superscript 0]like particles produced in association with a τlepton pair. These objects, with a similar mass and similar decay modes to π[superscript 0] mesons, could provide an explanation for the nonasymptotic behavior of the pionphoton transition form factor observed by the BABAR Collaboration. No significant signal is observed, and limits on the production cross section at the level of 73 fb or 370 fb, depending on the model parameters, are determined at 90% confidence level. These upper limits lie below the cross section values needed to explain the BABAR form factor data.  [Show abstract] [Hide abstract]
ABSTRACT: We use (121 ± 1) million Υ(3S) and (98 ± 1) million Υ(2S) mesons recorded by the BABAR detector at the PEPII e[superscript +]e[superscript ] collider at SLAC to perform a study of radiative transitions involving the χ[subscript bJ](1P,2P) states in exclusive decays with μ[superscript +]μ[superscript ]γγ final states. We reconstruct twelve channels in four cascades using two complementary methods. In the first we identify both signal photon candidates in the electromagnetic calorimeter (EMC), employ a calorimeter timingbased technique to reduce backgrounds, and determine branchingratio products and fine mass splittings. These results include the best observational significance yet for the χ[subscript b0](2P) → γΥ(2S) and χ[subscript b0](1P) → γΥ(1S) transitions. In the second method, we identify one photon candidate in the EMC and one which has converted into an e[superscript +]e[superscript ] pair due to interaction with detector material, and we measure absolute product branching fractions. This method is particularly useful for measuring Υ(3S) → γχ[subscript b1,2](1P) decays. Additionally, we provide the most uptodate derived branching fractions, matrix elements and mass splittings for χ[subscript b] transitions in the bottomonium system. Using a new technique, we also measure the two lowestorder spindependent coefficients in the nonrelativistic QCD Hamiltonian. 
Article: Measurement of Prompt ψ(2S) to J/ψ Yield Ratios in PbPb and pp Collisions at sqrt[s_NN]=2.76 TeV.
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ABSTRACT: The ratio between the prompt ψ(2S) and J/ψ yields, reconstructed via their decays into μ^+μ^, is measured in PbPb and pp collisions at sqrt[s_NN]=2.76 TeV. The analysis is based on PbPb and pp data samples collected by CMS at the Large Hadron Collider, corresponding to integrated luminosities of 150 μb^1 and 5.4 pb^1, respectively. The double ratio of measured yields (N_ψ(2S)/N_J/ψ)_PbPb/(N_ψ(2S)/N_J/ψ)_pp is computed in three PbPb collision centrality bins and two kinematic ranges: one at midrapidity, y<1.6, covering the transverse momentum range 6.5<p_T<30 GeV/c, and the other at forward rapidity, 1.6<y<2.4, extending to lower p_T values, 3<p_T<30 GeV/c. The centralityintegrated double ratio changes from 0.45±0.13(stat)±0.07(syst) in the first range to 1.67±0.34(stat)±0.27(syst) in the second. This difference is most pronounced in the most central collisions.
Publication Stats
6k  Citations  
3,513.63  Total Impact Points  
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Institutions

19932013

University of Colorado at Boulder
 Department of Physics
Boulder, Colorado, United States


20072008

Université de Savoie
Chambéry, RhôneAlpes, France


20022005

RuhrUniversität Bochum
 Institut für Experimentalphysik I
Bochum, North RhineWestphalia, Germany


19952000

Carleton University
Ottawa, Ontario, Canada


19912000

The Ohio State University
 Department of Educational Studies
Columbus, Ohio, United States


1997

Harvard University
Cambridge, Massachusetts, United States


1994

Cornell University
 Department of Electrical and Computer Engineering
Итак, New York, United States
