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Author |
LHCb Collaboration (Aaij, R. et al); Jashal, B.K.; Martinez-Vidal, F.; Oyanguren, A.; Remon Alepuz, C.; Ruiz Vidal, J. |
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Title |
Measurement of the Nuclear Modification Factor and Prompt Charged Particle Production in p-Pb and pp Collisions at root s(NN )=5 TeV |
Type |
Journal Article |
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Year |
2022 |
Publication |
Physical Review Letters |
Abbreviated Journal  |
Phys. Rev. Lett. |
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Volume |
128 |
Issue |
14 |
Pages |
142004 - 12pp |
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Abstract |
The production of prompt charged particles in proton-lead collisions and in proton-proton collisions at the nucleon-nucleon center-of-mass energy root s(NN) = 5 TeV is studied at LHCb as a function of pseudorapidity (eta) and transverse momentum (p(T) ) with respect to the proton beam direction. The nuclear modification factor for charged particles is determined as a function of eta between -4.8 < eta < -2.5 (backward region) and 2.0 < eta < 4.8 (forward region), and p(T) between 0.2 < p(T) < 8.0 GeV/c. The results show a suppression of charged particle production in proton-lead collisions relative to proton-proton collisions in the forward region and an enhancement in the backward region for p(T) larger than 1.5 GeV/c. This measurement constrains nuclear PDFs and saturation models at previously unexplored values of the parton momentum fraction down to 10(-6). |
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Address |
[Leite, J. Baptista; Bediaga, I; Torres, M. Cruz; De Miranda, J. M.; dos Reis, A. C.; Gomes, A.; Massafferri, A.; Machado, D. Torres] Ctr Brasileiro Pesquisas Fis CBPF, Rio De Janeiro, Brazil |
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Amer Physical Soc |
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English |
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ISSN |
0031-9007 |
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Conference |
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Notes |
WOS:000792795000003 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
5233 |
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Author |
LHCb Collaboration (Aaij, R. et al); Jashal, B.K.; Martinez-Vidal, F.; Oyanguren, A.; Remon Alepuz, C.; Ruiz Vidal, J. |
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Title |
Observation of two new excited Ξ0b states decaying to Λ0bK−π+ |
Type |
Journal Article |
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Year |
2022 |
Publication |
Physical Review Letters |
Abbreviated Journal |
Phys. Rev. Lett. |
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Volume |
128 |
Issue |
16 |
Pages |
162001 - 12pp |
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Keywords |
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Abstract |
Two narrow resonant states are observed in the Λ0bK−π+ mass spectrum using a data sample of proton-proton collisions at a center-of-mass energy of 13 TeV, collected by the LHCb experiment and corresponding to an integrated luminosity of 6 fb−1. The minimal quark content of the Λ0bK−π+ system indicates that these are excited Ξ0b baryons. The masses of the Ξb(6327)0 and Ξb(6333)0 states are m(Ξb(6327)0)=6327.28+0.23−0.21±0.12±0.24 MeV and m(Ξb(6333)0)=6332.69+0.17−0.18±0.03±0.22 MeV, respectively, with a mass splitting of Δm=5.41+0.26−0.27±0.12 MeV, where the uncertainties are statistical, systematic and due to the Λ0b mass measurement. The measured natural widths of these states are consistent with zero, with upper limits of Γ(Ξb(6327)0)<2.20 (2.56) MeV and Γ(Ξb(6333)0)<1.60 (1.92) MeV at a 90% (95%) credibility level. The significance of the two-peak hypothesis is larger than nine (five) Gaussian standard deviations compared to the no-peak (one-peak) hypothesis. The masses, widths and resonant structure of the new states are in good agreement with the expectations for a doublet of 1D Ξ0b resonances. |
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Address |
[Leite, J. Baptista; Bediaga, I; Torres, M. Cruz; De Miranda, J. M.; dos Reis, A. C.; Gomes, A.; Massafferri, A.; Machado, D. Torres] Ctr Brasileiro Pesquisas Fis CBPF, 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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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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ISSN |
0031-9007 |
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Expedition |
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Conference |
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Notes |
WOS:000802651800002 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
5241 |
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Author |
BABAR Collaboration (Lees, J.P. et al); Martinez-Vidal, F.; Oyanguren, A. |
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Title |
Search for an Axionlike Particle in B Meson Decays |
Type |
Journal Article |
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Year |
2022 |
Publication |
Physical Review Letters |
Abbreviated Journal |
Phys. Rev. Lett. |
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Volume |
128 |
Issue |
13 |
Pages |
131802 - 8pp |
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Keywords |
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Abstract |
Axionlike particles (ALPs) are predicted in many extensions of the standard model, and their masses can naturally be well below the electroweak scale. In the presence of couplings to electroweak bosons, these particles could be emitted in flavor-changing B meson decays. We report herein a search for an ALP, a, in the reaction B-+/- -> K(+/-)a, a -> gamma gamma using data collected by the BABAR experiment at SLAC. No significant signal is observed, and 90% confidence level upper limits on the ALP coupling to electroweak bosons are derived as a function of ALP mass, improving current constraints by several orders of magnitude in the range 0.175 GeV < m(a) < 4.78 GeV. |
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Address |
[Lees, J. P.; Poireau, V; Tisserand, V] Univ Savoie, Lab Annecy Le Vieux Phys Particules LAPP, CNRS IN2P3, F-74941 Annecy Le Vieux, France |
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Amer Physical Soc |
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English |
Summary Language |
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ISSN |
0031-9007 |
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Notes |
WOS:000804568000011 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
5242 |
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Author |
LHCb Collaboration (Aaij, R. et al); Jashal, B.K.; Martinez-Vidal, F.; Oyanguren, A.; Remon Alepuz, C.; Ruiz Vidal, J. |
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Title |
Tests of Lepton Universality Using B-0 -> K(S)(0)l(+) l(-) and B+ -> K*(+)l(+)l(-) Decays |
Type |
Journal Article |
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Year |
2022 |
Publication |
Physical Review Letters |
Abbreviated Journal |
Phys. Rev. Lett. |
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Volume |
128 |
Issue |
19 |
Pages |
191802 - 15pp |
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Keywords |
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Abstract |
Tests of lepton universality in B-0 -> K(S)(0)l(+)l(-) and B+ -> K*(+)l(+)l(-) decays where l is either an electron or a muon are presented. The differential branching fractions of B-0 -> K(S)(0)e(+)e(-) and B+ -> K*(+)e(+)e(-) decays are measured in intervals of the dilepton invariant mass squared. The measurements are performed using proton-proton collision data recorded by the LHCb experiment, corresponding to an integrated luminosity of 9 fb(-1). The results are consistent with the standard model and previous tests of lepton universality in related decay modes. The first observation of B-0 -> K(S)(0)e(+)e(-) and B+ -> K*(+)e(+)e(-) decays is reported. |
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Address |
[Leite, J. Baptista; Bediaga, I; Torres, M. Cruz; De Miranda, J. M.; dos Reis, A. C.; Falcao, L. N.; Gomes, A.; Massafferri, A.; Machado, D. Torres] Ctr Brasileiro Pesquisas Fis CBPF, Rio De Janeiro, Brazil |
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Corporate Author |
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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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Medium |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000801151800003 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
5247 |
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| Permanent link to this record |
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Author |
LHCb Collaboration (Aaij, R. et al); Jashal, B.K.; Martinez-Vidal, F.; Oyanguren, A.; Remon Alepuz, C.; Ruiz Vidal, J. |
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Title |
Observation of the Decay Lambda(0)(b) -> Lambda(+)(c) tau(-)(nu)over-bar(tau) |
Type |
Journal Article |
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Year |
2022 |
Publication |
Physical Review Letters |
Abbreviated Journal |
Phys. Rev. Lett. |
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Volume |
128 |
Issue |
19 |
Pages |
191803 - 11pp |
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Keywords |
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Abstract |
The first observation of the semileptonic b-baryon decay Lambda(0)(b) -> Lambda(+)(c) tau(-)(nu) over bar (tau) with a significance of 6.1 sigma, is reported using a data sample corresponding to 3 fb(-1) of integrated luminosity, collected by the LHCb experiment at center-of-mass energies of 7 and 8 TeV at the LHC. The tau(-) lepton is reconstructed in the hadronic decay to three charged pions. The ratio K = B(Lambda(0)(b) -> Lambda(+)(c) tau(-)(nu) over bar (tau))/B(Lambda(0)(b) -> Lambda(+)(c)pi(-)pi(+)pi(-)) is measured to be 2.46 +/- 0.27 +/- 0.40, where the first uncertainty is statistical and the second systematic. The branching fraction B(Lambda(0)(b) -> Lambda(+)(c) tau(-)(nu) over bar (tau)) (1.50 +/- 0.16 +/- 0.25 +/- 0.23)% is obtained, where the third uncertainty is from the external branching fraction of the normalization channel Lambda(0)(b) -> Lambda(+)(c)pi(-)pi(+)pi(-). The ratio of semileptonic branching fractions R(Lambda(+)(c)) B(Lambda(0)(b) -> Lambda(+)(c) tau(-)(nu) over bar (tau))/B(Lambda(0)(b) -> Lambda(+)(c)mu(-)(nu) over bar (tau)) is derived to be 0.242 +/- 0.026 +/- 0.040 +/- 0.059, where the external branching fraction uncertainty from the channel Lambda(0)(b) -> Lambda(+)(c)mu(-)(nu) over bar (tau) contributes to the last term. This result is in agreement with the standard model prediction. |
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Address |
[de Souza Leite, J. Baptista; Bediaga, I; Torres, M. Cruz; Carneiro Da Graca, U. De Freitas; De Miranda, J. M.; dos Reis, A. C.; Falcao, L. N.; Gomes, A.; Massafferri, A.; Machado, D. Torres] Ctr Brasileiro Pesquisas Fis CBPF, Rio De Janeiro, Brazil |
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Corporate Author |
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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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Medium |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000807542100003 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
5254 |
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| Permanent link to this record |
