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P. Achard,
O Adriani,
M. Aguilar-Benitez,
M. van den Akker,
J Alcaraz,
G. Alemanni,
J. Allaby,
A Aloisio,
M G Alviggi,
H Anderhub, [......],
J H Field,
F. Filthaut,
W Fisher,
I Fisk,
G Forconi,
K. Freudenreich,
C Furetta,
Y. Galaktionov,
S N Ganguli,
P. Garcia-Abia
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S Chatrchyan,
V Khachatryan,
A M Sirunyan,
A Tumasyan,
W Adam,
E Aguilo,
T Bergauer,
M Dragicevic,
J Erö,
C Fabjan, [......],
R Loveless,
A Mohapatra,
M U Mozer,
I Ojalvo,
F Palmonari,
G A Pierro,
I Ross,
A Savin,
W H Smith,
J Swanson
[show abstract]
[hide abstract]
ABSTRACT: A study is presented of the mass and spin-parity of the new boson recently observed at the LHC at a mass near 125 GeV. An integrated luminosity of 17.3 fb^{-1}, collected by the CMS experiment in proton-proton collisions at center-of-mass energies of 7 and 8 TeV, is used. The measured mass in the ZZ channel, where both Z bosons decay to e or μ pairs, is 126.2±0.6(stat)±0.2(syst) GeV. The angular distributions of the lepton pairs in this channel are sensitive to the spin-parity of the boson. Under the assumption of spin 0, the present data are consistent with the pure scalar hypothesis, while disfavoring the pure pseudoscalar hypothesis.
Physical Review Letters 02/2013; 110(8):081803. · 7.37 Impact Factor
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S Chatrchyan,
V Khachatryan,
A M Sirunyan,
A Tumasyan,
W Adam,
E Aguilo,
T Bergauer,
M Dragicevic,
J Erö,
C Fabjan, [......],
J Leonard,
R Loveless,
A Mohapatra,
I Ojalvo,
F Palmonari,
G A Pierro,
I Ross,
A Savin,
W H Smith,
J Swanson
[show abstract]
[hide abstract]
ABSTRACT: Results are presented from a search for the pair production of third-generation scalar and vector leptoquarks, as well as for top squarks in R-parity-violating supersymmetric models. In either scenario, the new, heavy particle decays into a τ lepton and a b quark. The search is based on a data sample of pp collisions at sqrt[s]=7 TeV, which is collected by the CMS detector at the LHC and corresponds to an integrated luminosity of 4.8 fb^{-1}. The number of observed events is found to be in agreement with the standard model prediction, and exclusion limits on mass parameters are obtained at the 95% confidence level. Vector leptoquarks with masses below 760 GeV are excluded and, if the branching fraction of the scalar leptoquark decay to a τ lepton and a b quark is assumed to be unity, third-generation scalar leptoquarks with masses below 525 GeV are ruled out. Top squarks with masses below 453 GeV are excluded for a typical benchmark scenario, and limits on the coupling between the top squark, τ lepton, and b quark, λ_{333}^{'} are obtained. These results are the most stringent for these scenarios to date.
Physical Review Letters 02/2013; 110(8):081801. · 7.37 Impact Factor
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S Chatrchyan,
V Khachatryan,
A M Sirunyan,
A Tumasyan,
W Adam,
E Aguilo,
T Bergauer,
M Dragicevic,
J Erö,
C Fabjan, [......],
C Lazaridis,
R Loveless,
A Mohapatra,
I Ojalvo,
F Palmonari,
G A Pierro,
I Ross,
A Savin,
W H Smith,
J Swanson
[show abstract]
[hide abstract]
ABSTRACT: The polarizations of the Υ(1S), Υ(2S), and Υ(3S) mesons are measured in proton-proton collisions at sqrt[s]=7 TeV, using a data sample of Υ(nS)→μ^{+}μ^{-} decays collected by the CMS experiment, corresponding to an integrated luminosity of 4.9 fb^{-1}. The dimuon decay angular distributions are analyzed in three different polarization frames. The polarization parameters λ_{ϑ}, λ_{φ}, and λ_{ϑφ}, as well as the frame-invariant quantity λ[over ˜], are presented as a function of the Υ(nS) transverse momentum between 10 and 50 GeV, in the rapidity ranges |y|<0.6 and 0.6<|y|<1.2. No evidence of large transverse or longitudinal polarizations is seen in the explored kinematic region.
Physical Review Letters 02/2013; 110(8):081802. · 7.37 Impact Factor
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P. Bagnaia,
A. Bajo,
G. Baksay,
L. Baksay,
S. V. Baldew,
S. Banerjee,
A. Barczyk,
R. Barillere,
P. Bartalini,
M. Basile, [......],
R. van Gulik,
V. K. Gupta,
A. Gurtu,
L. J. Gutay,
D. Haas,
D. Hatzifotiadou,
T. Hebbeker,
A. Herve,
J. Hirschfelder,
H. Hofer
-
P. Bagnaia,
A. Bajo,
G. Baksay,
L. Baksay,
S. V. Baldew,
S. Banerjee,
A. Barczyk,
R. Barillere,
P. Bartalini,
M. Basile, [......],
R. van Gulik,
V. K. Gupta,
A. Gurtu,
L. J. Gutay,
D. Haas,
D. Hatzifotiadou,
T. Hebbeker,
A. Herve,
J. Hirschfelder,
H. Hofer
-
P. Achard,
O Adriani,
M. Aguilar-Benitez,
M. van den Akker,
J Alcaraz,
G. Alemanni,
J. Allaby,
A Aloisio,
M G Alviggi,
H Anderhub, [......],
W Fisher,
G Forconi,
K. Freudenreich,
C Furetta,
Y. Galaktionov,
S N Ganguli,
P. Garcia-Abia,
M. Gataullin,
S Gentile,
S Giagu
-
M. Acciarri,
P. Achard,
O. Adriani,
M. Aguilar-Benitez,
J. Alcaraz,
G. Alemanni,
J. Allaby,
A. Aloisio,
M.G. Alviggi,
G. Ambrosi, [......],
F.C. Erné,
P. Extermann,
M. Fabre,
R. Faccini,
M.A. Falagan,
S. Falciano,
A. Favara,
J. Fay,
O. Fedin,
M. Felcini
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S Chatrchyan,
V Khachatryan,
A M Sirunyan,
A Tumasyan,
W Adam,
E Aguilo,
T Bergauer,
M Dragicevic,
J Erö,
C Fabjan, [......],
J Leonard,
R Loveless,
A Mohapatra,
I Ojalvo,
F Palmonari,
G A Pierro,
I Ross,
A Savin,
W H Smith,
J Swanson
[show abstract]
[hide abstract]
ABSTRACT: Evidence is presented for the associated production of a single top quark and W boson in pp collisions at sqrt[s]=7 TeV with the CMS experiment at the LHC. The analyzed data correspond to an integrated luminosity of 4.9 fb^{-1}. The measurement is performed using events with two leptons and a jet originated from a b quark. A multivariate analysis based on kinematic properties is utilized to separate the tt[over ¯] background from the signal. The observed signal has a significance of 4.0σ and corresponds to a cross section of 16_{-4}^{+5} pb, in agreement with the standard model expectation of 15.6±0.4_{-1.2}^{+1.0} pb.
Physical Review Letters 01/2013; 110(2):022003. · 7.37 Impact Factor
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S Chatrchyan,
V Khachatryan,
A M Sirunyan,
A Tumasyan,
W Adam,
E Aguilo,
T Bergauer,
M Dragicevic,
J Erö,
C Fabjan, [......],
C Lazaridis,
R Loveless,
A Mohapatra,
I Ojalvo,
F Palmonari,
G A Pierro,
I Ross,
A Savin,
W H Smith,
J Swanson
[show abstract]
[hide abstract]
ABSTRACT: Results are presented from a search for heavy, right-handed muon neutrinos, N_{μ}, and right-handed W_{R} bosons, which arise in the left-right symmetric extensions of the standard model. The analysis is based on a 5.0 fb^{-1} sample of proton-proton collisions at a center-of-mass energy of 7 TeV, collected by the CMS detector at the Large Hadron Collider. No evidence is observed for an excess of events over the standard model expectation. For models with exact left-right symmetry, heavy right-handed neutrinos are excluded at 95% confidence level for a range of neutrino masses below the W_{R} mass, dependent on the value of M_{W_{R}}. The excluded region in the two-dimensional (M_{W_{R}}, M_{N_{μ}}) mass plane extends to M_{W_{R}}=2.5 TeV.
Physical Review Letters 12/2012; 109(26):261802. · 7.37 Impact Factor
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S Chatrchyan,
V Khachatryan,
A M Sirunyan,
A Tumasyan,
W Adam,
E Aguilo,
T Bergauer,
M Dragicevic,
J Erö,
C Fabjan, [......],
J Leonard,
R Loveless,
A Mohapatra,
I Ojalvo,
F Palmonari,
G A Pierro,
I Ross,
A Savin,
W H Smith,
J Swanson
[show abstract]
[hide abstract]
ABSTRACT: We report an investigation of the invariant mass spectrum of the two jets with highest transverse momentum in pp→W+2-jet and W+3-jet events to look for resonant enhancement. The data sample corresponds to an integrated luminosity of 5.0 fb^{-1} collected with the CMS detector at sqrt[s]=7 TeV. We find no evidence for the anomalous structure reported by the CDF Collaboration, and establish an upper limit of 5.0 pb at 95% confidence level on the production cross section for a generic Gaussian signal with mass near 150 GeV. Additionally, we exclude two theoretical models that predict a CDF-like dijet resonance near 150 GeV.
Physical Review Letters 12/2012; 109(25):251801. · 7.37 Impact Factor
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D. Abbaneo,
G. Abbiendi,
M. Abbrescia,
S. Abdullin,
A. Abdulsalam,
B.S. Acharya,
D. Acosta,
J.G. Acosta,
A. Adair,
W. Adam, [......],
M.H. Zoeller,
O. Zorba,
P. Zotto,
W. Zou,
G. Zumerle,
M. Zupan,
A. Zuranski,
R. Zuyeuski,
M. Zvada,
P. Zych
[show abstract]
[hide abstract]
ABSTRACT: The Higgs boson was postulated nearly five decades ago within the framework of the standard model of particle physics and
has been the subject of numerous searches at accelerators around the world. Its discovery would verify the existence of a
complex scalar field thought to give mass to three of the carriers of the electroweak force—the W+, W–, and Z0 bosons—as well as to the fundamental quarks and leptons. The CMS Collaboration has observed, with a statistical significance
of five standard deviations, a new particle produced in proton-proton collisions at the Large Hadron Collider at CERN. The
evidence is strongest in the diphoton and four-lepton (electrons and/or muons) final states, which provide the best mass resolution
in the CMS detector. The probability of the observed signal being due to a random fluctuation of the background is about 1
in 3 × 106. The new particle is a boson with spin not equal to 1 and has a mass of about 1.25 giga–electron volts. Although its measured
properties are, within the uncertainties of the present data, consistent with those expected of the Higgs boson, more data
are needed to elucidate the precise nature of the new particle.
Science 12/2012; 338(6114):1569-1575. · 31.20 Impact Factor
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M. Acciarri,
P. Achard,
O. Adriani,
M. Aguilar-Benitez,
J. Alcaraz,
G. Alemanni,
J. Allaby,
A. Aloisio,
M.G. Alviggi,
G. Ambrosi, [......],
F.C. Erné,
P. Extermann,
M. Fabre,
R. Faccini,
M.A. Falagan,
S. Falciano,
A. Favara,
J. Fay,
O. Fedin,
M. Felcini
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S Chatrchyan,
V Khachatryan,
A M Sirunyan,
A Tumasyan,
W Adam,
E Aguilo,
T Bergauer,
M Dragicevic,
J Erö,
C Fabjan, [......],
J Leonard,
R Loveless,
A Mohapatra,
I Ojalvo,
F Palmonari,
G A Pierro,
I Ross,
A Savin,
W H Smith,
J Swanson
[show abstract]
[hide abstract]
ABSTRACT: The suppression of the individual Υ(nS) states in PbPb collisions with respect to their yields in pp data has been measured. The PbPb and pp data sets used in the analysis correspond to integrated luminosities of 150 μb^{-1} and 230 nb^{-1}, respectively, collected in 2011 by the CMS experiment at the LHC, at a center-of-mass energy per nucleon pair of 2.76 TeV. The Υ(nS) yields are measured from the dimuon invariant mass spectra. The suppression of the Υ(nS) yields in PbPb relative to the yields in pp, scaled by the number of nucleon-nucleon collisions, R_{AA}, is measured as a function of the collision centrality. Integrated over centrality, the R_{AA} values are 0.56±0.08(stat)±0.07(syst), 0.12±0.04(stat)±0.02(syst), and lower than 0.10 (at 95% confidence level), for the Υ(1S), Υ(2S), and Υ(3S) states, respectively. The results demonstrate the sequential suppression of the Υ(nS) states in PbPb collisions at LHC energies.
Physical Review Letters 11/2012; 109(22):222301. · 7.37 Impact Factor
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S Chatrchyan,
V Khachatryan,
A M Sirunyan,
A Tumasyan,
W Adam,
T Bergauer,
M Dragicevic,
J Erö,
C Fabjan,
M Friedl, [......],
J Leonard,
R Loveless,
A Mohapatra,
I Ojalvo,
F Palmonari,
G A Pierro,
I Ross,
A Savin,
W H Smith,
J Swanson
[show abstract]
[hide abstract]
ABSTRACT: A search for physics beyond the standard model is performed in events with at least three jets and large missing transverse momentum produced in proton-proton collisions at a center-of-mass energy of sqrt[s]=7 TeV. No significant excess of events above the expected backgrounds is observed in 4.98 fb^{-1} of data collected with the CMS detector at the Large Hadron Collider. The results are presented in the context of the constrained minimal supersymmetric extension of the standard model and more generically for simplified models. For the simplified models of gluino-gluino and squark-squark production, gluino masses below 1.0 TeV and squark masses below 0.76 TeV are excluded in case the lightest supersymmetric particle mass is below 200 GeV. These results significantly extend previous searches.
Physical Review Letters 10/2012; 109(17):171803. · 7.37 Impact Factor
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S Chatrchyan,
V Khachatryan,
A M Sirunyan,
A Tumasyan,
W Adam,
T Bergauer,
M Dragicevic,
J Erö,
C Fabjan,
M Friedl, [......],
J Leonard,
R Loveless,
A Mohapatra,
I Ojalvo,
F Palmonari,
G A Pierro,
I Ross,
A Savin,
W H Smith,
J Swanson
[show abstract]
[hide abstract]
ABSTRACT: The transverse energy (E_{T}) in Pb-Pb collisions at 2.76 TeV nucleon-nucleon center-of-mass energy (sqrt[s_{NN}]) has been measured over a broad range of pseudorapidity (η) and collision centrality by using the CMS detector at the LHC. The transverse energy density per unit pseudorapidity (dE_{T}/dη) increases faster with collision energy than the charged particle multiplicity. This implies that the mean energy per particle is increasing with collision energy. At all pseudorapidities, the transverse energy per participating nucleon increases with the centrality of the collision. The ratio of transverse energy per unit pseudorapidity in peripheral to central collisions varies significantly as the pseudorapidity increases from η=0 to |η|=5.0. For the 5% most central collisions, the energy density per unit volume is estimated to be about 14 GeV/fm^{3} at a time of 1 fm/c after the collision. This is about 100 times larger than normal nuclear matter density and a factor of 2.6 times higher than the energy density reported at sqrt[s_{NN}]=200 GeV at the Relativistic Heavy Ion Collider.
Physical Review Letters 10/2012; 109(15):152303. · 7.37 Impact Factor
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S Chatrchyan,
V Khachatryan,
A M Sirunyan,
A Tumasyan,
W Adam,
E Aguilo,
T Bergauer,
M Dragicevic,
J Erö,
C Fabjan, [......],
J Leonard,
R Loveless,
A Mohapatra,
I Ojalvo,
F Palmonari,
G A Pierro,
I Ross,
A Savin,
W H Smith,
J Swanson
[show abstract]
[hide abstract]
ABSTRACT: A search is performed in pp collisions at sqrt[s]=7 TeV for exotic particles decaying via WZ to final states with electrons and muons. The data sample corresponds to an integrated luminosity of approximately 5 fb^{-1}. No significant excess is observed in the data above the expected standard model background. Upper bounds at 95% confidence level are set on the production cross section of the W^{'} boson described by the sequential standard model and on the W^{'} WZ coupling. W^{'} bosons with masses below 1143 GeV are excluded. Limits are also set in the context of low-scale technicolor models, under a range of assumptions concerning the model parameters.
Physical Review Letters 10/2012; 109(14):141801. · 7.37 Impact Factor
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M. Vecchi,
L. Basara,
G. Bigongiari,
F. Cervelli,
G. Chen, G. M. Chen,
H. S. Chen,
G. Coignet,
S. Di Falco,
S. Elles, [......],
V. Lepareur,
Z. H. Li,
M. Maire,
M. Paniccia,
F. Pilo,
S. Rosier-Lees,
X. W. Tang,
C. Vannini,
J. P. Vialle,
H. L. Zhuang
[show abstract]
[hide abstract]
ABSTRACT: The electromagnetic calorimeter (ECAL) of the AMS-02 experiment is a
3-dimensional sampling calorimeter, made of lead and scintillating fibers. The
detector allows for a high granularity, with 18 samplings in the longitudinal
direction, and 72 sampling in the lateral direction. The ECAL primary goal is
to measure the energy of cosmic rays up to few TeV, however, thanks to the fine
grained structure, it can also provide the separation of positrons from
protons, in the GeV to TeV region. A direct measurement of high energy photons
with accurate energy and direction determination can also be provided.
10/2012;
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S Chatrchyan,
V Khachatryan,
A M Sirunyan,
A Tumasyan,
W Adam,
T Bergauer,
M Dragicevic,
J Erö,
C Fabjan,
M Friedl, [......],
J Leonard,
R Loveless,
A Mohapatra,
I Ojalvo,
F Palmonari,
G A Pierro,
I Ross,
A Savin,
W H Smith,
J Swanson
[show abstract]
[hide abstract]
ABSTRACT: The dimuon invariant mass spectrum is searched in the range between 5.5 and 14 GeV for a light pseudoscalar Higgs boson a, predicted in a number of new physics models, including the next-to-minimal supersymmetric standard model. The data sample used in the search corresponds to an integrated luminosity of 1.3 fb^{-1} collected in pp collisions at sqrt[s]=7 TeV with the CMS detector at the LHC. No excess is observed above the background predictions and upper limits are set on the cross section times branching fraction σ×B(pp→a→μ^{+}μ^{-}) in the range of 1.5-7.5 pb. These results improve on existing bounds on the abb[over ¯] coupling for m_{a}<m_{Υ(1S)} and are the first significant limits for m_{a}>m_{Υ(3S)}. Constraints on the supersymmetric parameter space are presented in the context of the next-to-minimal model.
Physical Review Letters 09/2012; 109(12):121801. · 7.37 Impact Factor
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[show abstract]
[hide abstract]
ABSTRACT: A DNA vaccine against the hepatitis B virus (HBV), enhanced by IL-2/IFN-γ fusion protein expression from a plasmid construct and mediated by in vivo electroporation, was evaluated in a total of 39 HBeAg-positive patients with chronic hepatitis B (CHB). The six of 39 patients with a serum alanine aminotransferase (ALT) value of 1-2 times upper limit of normal (ULN) were assigned to the open-label arm (Group01) receiving vaccine monotherapy; the remaining 33 patients with an ALT of more than two times ULN were enroled to the randomized and controlled arm (Group02) receiving lamivudine (LAM) monotherapy (LAM+placebo) or combined therapy (LAM+DNA vaccine) in 1:2 ratio. In Group01, a significant elevation of HBV-specific IFN-γ-secreting T-cell counts in comparison with baseline was observed. In Group02, the proportion of patients with HBV DNA suppression was higher with LAM+DNA vaccine than with LAM monotherapy at each visit time point after the final injection of DNA vaccine at week 36, revealing a significant difference between the two groups (P = 0.03) at week 60. The incidence of dual-site mutations of rtM204/I/S+rtL180M was significantly lower (P = 0.03) with an identified lower virological breakthrough (VBT) rate (P = 0.03) in patients receiving LAM+DNA vaccine than LAM monotherapy, accompanied with a significant higher positive T-cell response rate in patients receiving LAM+DNA vaccine (P = 0.03). In conclusion, this study provides evidence that HBV DNA vaccination is safe and immunologically effective, and that the HBV-specific T-cell responses induced by DNA vaccination under LAM chemotherapy showed a correlation with the suppression of viral replication in patients with CHB.
Journal of Viral Hepatitis 08/2012; 19(8):581-93. · 4.09 Impact Factor
