-
ALICE Collaboration,
B. Abelev,
J. Adam,
D. Adamová,
A. M. Adare,
M. M. Aggarwal,
G. Aglieri Rinella,
A. G. Agocs,
A. Agostinelli,
S. Aguilar Salazar, [......],
X. Zhang,
Y. Zhou,
D. Zhou,
F. Zhou,
X. Zhu,
A. Zichichi,
A. Zimmermann,
G. Zinovjev,
Y. Zoccarato,
M. Zynovyev
[show abstract]
[hide abstract]
ABSTRACT: The production of muons from heavy flavour decays is measured at forward
rapidity in proton-proton collisions at s=7 TeV collected with the
ALICE experiment at the LHC. The analysis is carried out on a data
sample corresponding to an integrated luminosity L=16.5
nb. The transverse momentum and rapidity differential
production cross sections of muons from heavy flavour decays are
measured in the rapidity range 2.5<y<4, over the transverse
momentum range 2<p<12 GeV/c. The results are compared
to predictions based on perturbative QCD calculations.
Physics Letters B 01/2012; 708:265-275. · 3.95 Impact Factor
-
K Aamodt,
B Abelev,
A Abrahantes Quintana,
D Adamova,
A M Adare,
M M Aggarwal,
Aglieri G Rinella,
A G Agocs,
A Agostinelli,
S Aguilar Salazar, [......],
D Zhou,
F Zhou,
Y Zhou,
X Zhu,
A Zichichi,
A Zimmermann,
G Zinovjev,
Y Zoccarato,
M Zynovyev,
ALICE Collaboration
Physics Letters B 01/2012; 708(3-5):249-264. · 3.95 Impact Factor
-
B Abelev,
A Abrahantes Quintana,
D Adamova,
A M Adare,
M M Aggarwal,
Aglieri G Rinella,
A G Agocs,
A Agostinelli,
S Aguilar Salazar,
Z Ahammed, [......],
D Zhou,
Y Zhou,
F Zhou,
X Zhu,
A Zichichi,
A Zimmermann,
G Zinovjev,
Y Zoccarato,
M Zynovyev,
ALICE Collaboration
Physics Letters B 01/2012; 710(4-5):557-568. · 3.95 Impact Factor
-
B Abelev,
J Adam,
D Adamova,
A M Adare,
M M Aggarwal,
Aglieri G Rinella,
A G Agocs,
A Agostinelli,
S Aguilar Salazar,
Z Ahammed, [......],
Y Zhou,
J Zhu,
X Zhu,
A Zichichi,
A Zimmermann,
G Zinovjev,
Y Zoccarato,
M Zynovyev,
M Zyzak,
ALICE Collaboration
Physical Review D 01/2012; 86(11). · 4.56 Impact Factor
-
B Abelev,
J Adam,
D Adamova,
A M Adare,
M M Aggarwal,
Aglieri G Rinella,
A G Agocs,
A Agostinelli,
Aguilar S Salazar,
Z Ahammed, [......],
D Zhou,
Y Zhou,
F Zhou,
X Zhu,
A Zichichi,
A Zimmermann,
G Zinovjev,
Y Zoccarato,
M Zynovyev,
ALICE Collaboration
Physics Letters B 01/2012; 718(2):295-306. · 3.95 Impact Factor
-
B Abelev,
J Adam,
D Adamova,
A M Adare,
M M Aggarwal,
Aglieri G Rinella,
A G Agocs,
A Agostinelli,
S Aguilar Salazar,
Z Ahammed, [......],
Y Zhou,
J Zhu,
X Zhu,
A Zichichi,
A Zimmermann,
G Zinovjev,
Y Zoccarato,
M Zynovyev,
M Zyzak,
ALICE Collaboration
Physics Letters B 01/2012; 717(1-3):151-161. · 3.95 Impact Factor
-
B. Abelev,
A. Abrahantes Quintana,
D. Adamová,
A. M. Adare,
M. M. Aggarwal,
G. Aglieri Rinella,
A. G. Agocs,
A. Agostinelli,
S. Aguilar Salazar,
Z. Ahammed, [......],
X. Zhang,
F. Zhou,
D. Zhou,
Y. Zhou,
X. Zhu,
A. Zichichi,
A. Zimmermann,
G. Zinovjev,
Y. Zoccarato,
M. Zynovyev
[show abstract]
[hide abstract]
ABSTRACT: The p t-differential inclusive production cross sections of
the prompt charmed mesons D0, D+, and
D*+ in the rapidity range | y| < 0.5 were measured in
proton-proton collisions at sqrt {s} = 7{ }TeV at the LHC using the
ALICE detector. Reconstructing the decays D0 →
K-π+, D+ →
K-π+π+, D*+ →
D0π+, and their charge conjugates, about 8,400
D0, 2,900 D+, and 2,600 D*+ mesons with
1 < p t < 24 GeV/ c were counted, after selection cuts,
in a data sample of 3.14 × 108 events collected with a
minimum-bias trigger (integrated luminosity L int = 5
nb-1). The results are described within uncertainties by
predictions based on perturbative QCD.
Journal of High Energy Physics 12/2011; 1:128. · 5.83 Impact Factor
-
B. Abelev,
A. Abrahantes Quintana,
D. Adamová,
A. M. Adare,
M. M. Aggarwal,
G. Aglieri Rinella,
A. G. Agocs,
A. Agostinelli,
S. Aguilar Salazar,
Z. Ahammed, [......],
X. Zhang,
F. Zhou,
D. Zhou,
Y. Zhou,
X. Zhu,
A. Zichichi,
A. Zimmermann,
G. Zinovjev,
Y. Zoccarato,
M. Zynovyev
[show abstract]
[hide abstract]
ABSTRACT: The p t-differential inclusive production cross sections of
the prompt charmed mesons D0, D+, and
D*+ in the rapidity range | y| < 0.5 were measured in
proton-proton collisions at sqrt {s} = 7{ }TeV at the LHC using the
ALICE detector. Reconstructing the decays D0 →
K-π+, D+ →
K-π+π+, D*+ →
D0π+, and their charge conjugates, about 8,400
D0, 2,900 D+, and 2,600 D*+ mesons with
1 < p t < 24 GeV/ c were counted, after selection cuts,
in a data sample of 3.14 × 108 events collected with a
minimum-bias trigger (integrated luminosity L int = 5
nb-1). The results are described within uncertainties by
predictions based on perturbative QCD.
Journal of High Energy Physics 12/2011; 1:128. · 5.83 Impact Factor
-
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,
W Parker,
I Ross,
A Savin,
W H Smith,
J Swanson,
M Weinberg
[show abstract]
[hide abstract]
ABSTRACT: A search for pair-produced heavy vectorlike charge-2/3 quarks, T, in pp collisions at a center-of-mass energy of 7 TeV, is performed with the CMS detector at the LHC. Events consistent with the flavor-changing-neutral-current decay of a T quark to a top quark and a Z boson are selected by requiring two leptons from the Z-boson decay, as well as an additional isolated charged lepton. In a data sample corresponding to an integrated luminosity of 1.14 fb(-1), the number of observed events is found to be consistent with the standard model background prediction. Assuming a branching fraction of 100% for the decay T→tZ, a T quark with a mass less than 475 GeV/c(2) is excluded at the 95% confidence level.
Physical Review Letters 12/2011; 107(27):271802. · 7.37 Impact Factor
-
ALICE Collaboration,
B. Abelev,
A. Abrahantes Quintana,
D Adamová,
A. M. Adare,
M. M. Aggarwal,
G. Aglieri Rinella,
A. G. Agocs,
A. Agostinelli,
S. Aguilar Salazar, [......],
X Zhang,
D Zhou,
Y Zhou,
F Zhou,
X Zhu,
A. Zichichi,
A Zimmermann,
G. Zinovjev,
Y. Zoccarato,
M. Zynovyev
[show abstract]
[hide abstract]
ABSTRACT: The ALICE experiment has measured low-mass dimuon production in pp collisions
at \sqrt{s} = 7 TeV in the dimuon rapidity region 2.5<y<4. The observed dimuon
mass spectrum is described as a superposition of resonance decays (\eta, \rho,
\omega, \eta^{'}, \phi) into muons and semi-leptonic decays of charmed mesons.
The measured production cross sections for \omega and \phi are \sigma_\omega
(1<p_t<5 GeV/c,2.5<y<4) = 5.28 +- 0.54 (stat) +- 0.50 (syst) mb and
\sigma_\phi(1<p_t<5 GeV/c,2.5<y<4)=0.940 +- 0.084 (stat) +- 0.078 (syst) mb.
The differential cross sections d^2\sigma/dy dp_t are extracted as a function
of p_t for \omega and \phi. The ratio between the \rho and \omega cross section
is obtained. Results for the \phi are compared with other measurements at the
same energy and with predictions by models.
12/2011;
-
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,
W Parker,
I Ross,
A Savin,
W H Smith,
J Swanson,
M Weinberg
[show abstract]
[hide abstract]
ABSTRACT: A search for events with jets and missing transverse energy is performed in a data sample of pp collisions collected at √s=7 TeV by the CMS experiment at the LHC. The analyzed data sample corresponds to an integrated luminosity of 1.14 fb(-1). In this search, a kinematic variable α(T) is used as the main discriminator between events with genuine and misreconstructed missing transverse energy. No excess of events over the standard model expectation is found. Exclusion limits in the parameter space of the constrained minimal supersymmetric extension of the standard model are set. In this model, squark masses below 1.1 TeV are excluded at 95% C.L. Gluino masses below 1.1 TeV are also ruled out at 95% C.L. for values of the universal scalar mass parameter below 500 GeV.
Physical Review Letters 11/2011; 107(22):221804. · 7.37 Impact Factor
-
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,
F Palmonari,
D Reeder,
I Ross,
A Savin,
W H Smith,
J Swanson,
M Weinberg
[show abstract]
[hide abstract]
ABSTRACT: A study of events with missing transverse energy and an energetic jet is performed using pp collision data at a center-of-mass energy of 7 TeV. The data were collected by the CMS detector at the LHC, and correspond to an integrated luminosity of 36 pb(-1). An excess of these events over standard model contributions is a signature of new physics such as large extra dimensions and unparticles. The number of observed events is in good agreement with the prediction of the standard model, and significant extension of the current limits on parameters of new physics benchmark models is achieved.
Physical Review Letters 11/2011; 107(20):201804. · 7.37 Impact Factor
-
The ALICE Collaboration,
B. Abelev,
A. Abrahantes Quintana,
D. Adamova,
A. M. Adare,
M. M. Aggarwal,
G. Aglieri Rinella,
A. G. Agocs,
A. Agostinelli,
S. Aguilar Salazar, [......],
X Zhang,
F Zhou,
D Zhou,
Y Zhou,
X Zhu,
A. Zichichi,
A Zimmermann,
G. Zinovjev,
Y. Zoccarato,
M. Zynovyev
[show abstract]
[hide abstract]
ABSTRACT: The pt-differential inclusive production cross sections of the prompt charmed
mesons D0, D+, and D*+ in the rapidity range |y|<0.5 were measured in
proton-proton collisions at sqrt(s) = 7 TeV at the LHC using the ALICE
detector. Reconstructing the decays D0->K-pi+, D+->K-pi+pi+, D*+->D0pi+, and
their charge conjugates, about 8,400 D0, 2,900 D+, and 2,600 D*+ mesons with
1<pt<24 GeV/c were counted, after selection cuts, in a data sample of 3.14x10^8
events collected with a minimum-bias trigger (integrated luminosity L_int =
5/nb). The results are described within uncertainties by predictions based on
perturbative QCD.
11/2011;
-
The ALICE Collaboration,
B. Abelev,
A. Abrahantes Quintana,
D. Adamova,
A. M. Adare,
M. M. Aggarwal,
G. Aglieri Rinella,
A. G. Agocs,
A. Agostinelli,
S. Aguilar Salazar, [......],
X. Zhang,
F. Zhou,
D. Zhou,
Y. Zhou,
X. Zhu,
A. Zichichi,
A. Zimmermann,
G. Zinovjev,
Y. Zoccarato,
M. Zynovyev
[show abstract]
[hide abstract]
ABSTRACT: The ALICE Collaboration has studied J/psi production in pp collisions at
sqrt(s)=7 TeV at the LHC through its muon pair decay. The polar and azimuthal
angle distributions of the decay muons were measured, and results on the J/psi
polarization parameters lambda_theta and lambda_phi were obtained. The study
was performed in the kinematic region 2.5<y<4, 2<p_t<8 GeV/c, in the helicity
and Collins-Soper reference frames. In both frames, the polarization parameters
are compatible with zero, within uncertainties.
11/2011;
-
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,
W Parker,
I Ross,
A Savin,
W H Smith,
J Swanson,
M Weinberg
[show abstract]
[hide abstract]
ABSTRACT: A search for the rare decays B(s)(0) → μ+ μ- and B(0) → μ+ μ- is performed in pp collisions at sqrt[s] = 7 TeV, with a data sample corresponding to an integrated luminosity of 1.14 fb(-1), collected by the CMS experiment at the LHC. In both cases, the number of events observed after all selection requirements is consistent with expectations from background and standard-model signal predictions. The resulting upper limits on the branching fractions are B(B(s)(0) → μ+ μ-) < 1.9 × 10(-8) and B(B(0) → μ+ μ-)<4.6 × 10(-9), at 95% confidence level.
Physical Review Letters 11/2011; 107(19):191802. · 7.37 Impact Factor
-
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,
W. Parker,
I. Ross,
A. Savin,
W. H. Smith,
J. Swanson,
M. Weinberg
[show abstract]
[hide abstract]
ABSTRACT: The Drell-Yan differential cross section is measured in pp collisions at
sqrt {s} = 7 TeV, from a data sample collected with the CMS detector at
the LHC, corresponding to an integrated luminosity of 36
pb-1. The cross section measurement, normalized to the
measured cross section in the Z region, is reported for both the dimuon
and dielectron channels in the dilepton invariant mass range 15-600 GeV.
The normalized cross section values are quoted both in the full phase
space and within the detector acceptance. The effect of final state
radiation is also identified. The results are found to agree with
theoretical predictions.
Journal of High Energy Physics 09/2011; 10:007. · 5.83 Impact Factor
-
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,
F Palmonari,
D Reeder,
I Ross,
A Savin,
W H Smith,
J Swanson,
M Weinberg
[show abstract]
[hide abstract]
ABSTRACT: The inclusive jet cross section is measured in pp collisions with a center-of-mass energy of 7 TeV at the Large Hadron Collider using the CMS experiment. The data sample corresponds to an integrated luminosity of 34 pb(-1). The measurement is made for jet transverse momenta in the range 18-1100 GeV and for absolute values of rapidity less than 3. The measured cross section extends to the highest values of jet p(T) ever observed and, within the experimental and theoretical uncertainties, is generally in agreement with next-to-leading-order perturbative QCD predictions.
Physical Review Letters 09/2011; 107(13):132001. · 7.37 Impact Factor
-
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,
D Reeder,
I Ross,
A Savin,
W H Smith,
J Swanson,
M Weinberg
[show abstract]
[hide abstract]
ABSTRACT: A search for three-jet hadronic resonance production in pp collisions at a center-of-mass energy of 7 TeV has been conducted by the CMS Collaboration at the LHC, using a data sample corresponding to an integrated luminosity of 35 pb(-1). Events with high jet multiplicity and a large scalar sum of jet transverse momenta are analyzed using a signature-based approach. The number of expected standard model background events is found to be in good agreement with the observed events. Limits on the cross section times branching ratio are set in a model of gluino pair production with an R-parity-violating decay to three quarks, and the data rule out such particles within the mass range of 200 to 280 GeV/c2.
Physical Review Letters 09/2011; 107(10):101801. · 7.37 Impact Factor
-
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,
F. Palmonari,
D. Reeder,
I. Ross,
A. Savin,
W. H. Smith,
J. Swanson,
M. Weinberg
[show abstract]
[hide abstract]
ABSTRACT: A measurement of the t{bar{t}} production cross section in proton-proton
collisions at a centre-of-mass energy of 7 TeV has been performed at the
LHC with the CMS detector. The analysis uses a data sample corresponding
to an integrated luminosity of 36 pb-1 and is based on the
reconstruction of the final state with one isolated, high
transverse-momentum electron or muon and three or more hadronic jets.
The kinematic properties of the events are used to separate the
t{bar{t}} signal from W+jets and QCD multijet background events. The
measured cross section is 173^{+39}_{-32} (stat. + syst.) pb, consistent
with standard model expectations.
European Physical Journal C 08/2011; 71:1721. · 3.63 Impact Factor
-
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,
F Palmonari,
D Reeder,
I Ross,
A Savin,
W H Smith,
J Swanson,
M Weinberg
[show abstract]
[hide abstract]
ABSTRACT: Electroweak production of the top quark is measured for the first time in pp collisions at √=7 TeV, using a data set collected with the CMS detector at the LHC and corresponding to an integrated luminosity of 36 pb⁻¹. With an event selection optimized for t-channel production, two complementary analyses are performed. The first one exploits the special angular properties of the signal, together with background estimates from the data. The second approach uses a multivariate analysis technique to probe the compatibility with signal topology expected from electroweak top-quark production. The combined measurement of the cross section is 83.6±29.8(stat+syst)±3.3(lumi) pb, consistent with the standard model expectation.
Physical Review Letters 08/2011; 107(9):091802. · 7.37 Impact Factor
