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Author |
CMS and LHCb Collaborations (Khachatryan, V. et al); Martinez-Vidal, F.; Oyanguren, A.; Ruiz Valls, P.; Sanchez Mayordomo, C. |
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Title |
Observation of the rare B-s(0)->mu(+)mu(-) decay from the combined analysis of CMS and LHCb data |
Type |
Journal Article |
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Year |
2015 |
Publication |
Nature |
Abbreviated Journal |
Nature |
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Volume |
522 |
Issue |
7554 |
Pages |
68-72 |
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Keywords |
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Abstract |
The standard model of particle physics describes the fundamental particles and their interactions via the strong, electromagnetic and weak forces. It provides precise predictions for measurable quantities that can be tested experimentally. The probabilities, or branching fractions, of the strange B meson (B-s(0)) and the B-0 meson decaying into two oppositely charged muons (mu(+) and mu(-)) are especially interesting because of their sensitivity to theories that extend the standard model. The standard model predicts that the B-s(0)->mu(+)mu(-) and B-0 ->mu(+)mu(-) decays are very rare, with about four of the former occurring for every billion B-s(0) mesons produced, and one of the latter occurring for every ten billion B-0 mesons(1). A difference in the observed branching fractions with respect to the predictions of the standard model would provide a direction in which the standard model should be extended. Before the Large Hadron Collider (LHC) at CERN2 started operating, no evidence for either decay mode had been found. Upper limits on the branching fractions were an order of magnitude above the standard model predictions. The CMS (Compact Muon Solenoid) and LHCb(Large Hadron Collider beauty) collaborations have performed a joint analysis of the data from proton-proton collisions that they collected in 2011 at a centre-of-mass energy of seven teraelectronvolts and in 2012 at eight teraelectronvolts. Here we report the first observation of the B-s(0)->mu(+)mu(-) decay, with a statistical significance exceeding six standard deviations, and the best measurement so far of its branching fraction. Furthermore, we obtained evidence for the B-0 ->mu(+)mu(-) decay with a statistical significance of three standard deviations. Both measurements are statistically compatible with standard model predictions and allow stringent constraints to be placed on theories beyond the standard model. The LHC experiments will resume taking data in 2015, recording proton-proton collisions at a centre-of-mass energy of 13 teraelectronvolts, which will approximately double the production rates of B-s(0) and B-0 mesons and lead to further improvements in the precision of these crucial tests of the standard model. |
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Address |
[Khachatryan, V.; Sirunyan, A. M.; Tumasyan, A.] Yerevan Phys Inst, Yerevan 375036, Armenia |
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Publisher |
Nature Publishing Group |
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English |
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0028-0836 |
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Notes |
WOS:000355543400030 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
2250 |
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Author |
Davesne, D.; Meyer, J.; Pastore, A.; Navarro, J. |
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Title |
Partial wave decomposition of the N3LO equation of state |
Type |
Journal Article |
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Year |
2015 |
Publication |
Physica Scripta |
Abbreviated Journal |
Phys. Scr. |
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Volume |
90 |
Issue |
11 |
Pages |
114002 - 6pp |
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Keywords |
nuclear structure; equation of state; effective theory |
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Abstract |
By means of a partial wave decomposition, we separate their contributions to the equation of state (EoS) of symmetric nuclear matter for the N3LO pseudo-potential. In particular, we show that although both the tensor and the spin-orbit terms do not contribute to the EoS, they give a non-vanishing contribution to the separate (JLS) channels. |
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Address |
[Davesne, D.; Meyer, J.] Univ Lyon 1, CNRS, IN2P3, Inst Phys Nucl Lyon,UMR 5822, F-69622 Villeurbanne, France, Email: davesne@ipnl.in2p3.fr; |
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Publisher |
Iop Publishing Ltd |
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English |
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Edition |
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ISSN |
0031-8949 |
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Notes |
WOS:000366871100003 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
2508 |
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Author |
LHCb Collaboration (Aaij, R. et al); Martinez-Vidal, F.; Oyanguren, A.; Ruiz Valls, P.; Sanchez Mayordomo, C. |
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Title |
Observation of Two New Xi(-)(b) Baryon Resonances |
Type |
Journal Article |
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Year |
2015 |
Publication |
Physical Review Letters |
Abbreviated Journal |
Phys. Rev. Lett. |
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Volume |
114 |
Issue |
6 |
Pages |
062004 - 9pp |
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Keywords |
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Abstract |
Two structures are observed close to the kinematic threshold in the Xi(0)(b)pi(-) mass spectrum in a sample of proton-proton collision data, corresponding to an integrated luminosity of 3.0 fb(-1), recorded by the LEICb experiment. In the quark model, two baryonic resonances with quark content bds are expected in this mass region: the spin-parity J(P) = (1/2)(+) and J(P) = (3/2)(+) states, denoted Xi'(-)(b) and Xi*(-)(b). Interpreting the structures as these resonances, we measure the mass differences and the width of the heavier state to be m(Xi'(-)(b)) – m(Xi(0)(b)) – m(pi(-))=3.653 +/- 0.018 +/- 0.006 MeV/c(2), m(Xi*(-)(b)) – m(Xi(0)(b)) – m(pi(-)) = 23.96 +/- 0.12 +/- 0.06 MeV/e(2), Gamma(Xi*(-)(b)) = 1.65 +/- 0.31 +/- 0.10 MeV, where the first and second uncertainties are statistical and systematic, respectively. The width of the lighter state is consistent with zero, and we place an upper limit of Gamma(Xi'(-)(b)) < 0.08 MeV at 95% confidence level. Relative production rates of these states are also reported. |
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Address |
[Bediaga, I.; De Miranda, J. M.; Ferreira Rodrigues, F.; Gomes, A.; Massafferri, A.; dos Reis, A. C.; Rodrigues, A. B.] Ctr Brasileiro Pesquisas Fis, Rio De Janeiro, Brazil |
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Publisher |
Amer Physical Soc |
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English |
Summary Language |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0031-9007 |
ISBN |
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Notes |
WOS:000349490200004 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
2127 |
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Author |
ATLAS Collaboration (Aad, G. et al); Cabrera Urban, S.; Castillo Gimenez, V.; Costa, M.J.; Ferrer, A.; Fiorini, L.; Fuster, J.; Garcia, C.; Garcia Navarro, J.E.; Gonzalez de la Hoz, S.; Hernandez Jimenez, Y.; Higon-Rodriguez, E.; Irles Quiles, A.; Kaci, M.; King, M.; Lacasta, C.; Lacuesta, V.R.; Marti-Garcia, S.; Mitsou, V.A.; Moles-Valls, R.; Oliver Garcia, E.; Pedraza Lopez, S.; Perez Garcia-Estañ, M.T.; Romero Adam, E.; Ros, E.; Salt, J.; Sanchez Martinez, V.; Soldevila, U.; Sanchez, J.; Torro Pastor, E.; Valero, A.; Valladolid Gallego, E.; Valls Ferrer, J.A.; Vos, M. |
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Title |
Measurements of the Nuclear Modification Factor for Jets in Pb plus Pb Collisions at root SNN=2.76 TeV with the ATLAS Detector |
Type |
Journal Article |
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Year |
2015 |
Publication |
Physical Review Letters |
Abbreviated Journal |
Phys. Rev. Lett. |
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Volume |
114 |
Issue |
7 |
Pages |
072302 - 18pp |
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Keywords |
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Abstract |
Measurements of inclusive jet production are performed in pp and Pb + Pb collisions at root SNN = 2.76 TeV with the ATLAS detector at the LHC, corresponding to integrated luminosities of 4.0 and 0.14 nb(-1), respectively. The jets are identified with the anti-k(t) algorithm with R = 0.4, and the spectra are measured over the kinematic range of jet transverse momentum 32 < pT < 500 GeV and absolute rapidity |y| < 2.1 and as a function of collision centrality. The nuclear modification factor R-AA is evaluated, and jets are found to be suppressed by approximately a factor of 2 in central collisions compared to pp collisions. The RAA shows a slight increase with pT and no significant variation with rapidity. |
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Address |
[Jackson, P.; Soni, N.; White, M. J.] Univ Adelaide, Dept Phys, Adelaide, SA, Australia |
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Amer Physical Soc |
Place of Publication |
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English |
Summary Language |
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ISSN |
0031-9007 |
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Conference |
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Notes |
WOS:000349788000008 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
2136 |
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Author |
LHCb Collaboration (Aaij, R. et al); Martinez-Vidal, F.; Oyanguren, A.; Ruiz Valls, P.; Sanchez Mayordomo, C. |
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Title |
Measurement of the Semileptonic CP Asymmetry in B-0-(B)over-bar(0) Mixing |
Type |
Journal Article |
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Year |
2015 |
Publication |
Physical Review Letters |
Abbreviated Journal |
Phys. Rev. Lett. |
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Volume |
114 |
Issue |
4 |
Pages |
041601 - 9pp |
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Keywords |
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Abstract |
The semileptonic CP asymmetry in B-0-(B) over bar (0) mixing, a(s1)(d), is measured in proton-proton collision data, corresponding to an integrated luminosity of 3.0 fb(-1), recorded by the LHCb experiment. Semileptonic B-0 decays are reconstructed in the inclusive final states D-mu(+) and D*(-)mu(+), where the D- meson decays into the K+pi(-)pi(-) final state and the D*(-) meson into the (D) over bar (0)(-> K+pi(-))pi(-) final state. The asymmetry between the numbers of D-(*()-)mu(+) and D-(*()+)mu(-) decays is measured as a function of the decay time of the B-0 mesons. The CP asymmetry is measured to be a(s1)(d) = (-0.02 +/- 0.19 +/- 0.30)%, where the first uncertainty is statistical and the second systematic. This is the most precise measurement of a(s1)(d) to date and is consistent with the prediction from the standard model. |
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Address |
[Bediaga, I.; De Miranda, J. M.; Rodrigues, F. Ferreira; Gomes, A.; Kucewicz, W.; Massafferri, A.; dos Reis, A. C.; Rodrigues, A. B.] Ctr Brasileiro Pesquisas Fis, Rio De Janeiro, Brazil |
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Thesis |
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Publisher |
Amer Physical Soc |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0031-9007 |
ISBN |
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Conference |
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Notes |
WOS:000349871400002 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
2141 |
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