| Records |
| Author |
LHCb Collaboration (Aaij, R. et al); Jaimes Elles, S.J.; Jashal, B.K.; Martinez-Vidal, F.; Oyanguren, A.; Rebollo De Miguel, M.; Sanderswood, I.; Zhuo, J. |
| Title |
Measurement of J/ψ-pair production in pp collisions at √s=13 TeV and study of gluon transverse-momentum dependent PDFs |
Type |
Journal Article |
Year  |
2024 |
Publication |
Journal of High Energy Physics |
Abbreviated Journal |
J. High Energy Phys. |
| Volume |
03 |
Issue |
3 |
Pages |
088 - 40pp |
| Keywords |
Hadron-Hadron Scattering; Multi-Parton Interactions; QCD; Quarkonium |
| Abstract |
The production cross-section of J/psi pairs in proton-proton collisions at a centre-of-mass energy of root s = 13TeV is measured using a data sample corresponding to an integrated luminosity of 4.2 fb(-1) collected by the LHCb experiment. The measurement is performed with both J/psi mesons in the transverse momentum range 0 < p(T) < 14 GeV/c and rapidity range 2.0 < y < 4.5. The cross-section of this process is measured to be 16.36 +/- 0.28 (stat) +/- 0.88 (syst) nb. The contributions from single-parton scattering and double-parton scattering are separated based on the dependence of the cross-section on the absolute rapidity difference Delta y between the two J/psi mesons. The effective cross-section of double-parton scattering is measured to be sigma(eff) = 13.1 +/- 1.8 (stat) +/- 2.3 (syst) mb. The distribution of the azimuthal angle phi(CS) of one of the J/psi mesons in the Collins-Soper frame and the p(T)-spectrum of the J/psi pairs are also measured for the study of the gluon transverse-momentum dependent distributions inside protons. The extracted values of < cos4 phi(CS)> and < cos2 phi(CS)> are consistent with zero, but the presence of azimuthal asymmetry at a few percent level is allowed. |
| Address |
[Egede, U.; Fujii, Y.; Hadavizadeh, T.; Henderson, R. D. L.; Lane, J. J.; Monk, M.; Song, R.; Walton, E. J.; Ward, J. A.] Monash Univ, Sch Phys & Astron, Melbourne, Australia, Email: li.xu@cern.ch |
| Corporate Author |
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Thesis |
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| Publisher |
Springer |
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 |
1029-8479 |
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:001194594600001 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
6050 |
| Permanent link to this record |
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| Author |
LHCb Collaboration (Aaij, R. et al); Jaimes Elles, S.J.; Jashal, B.K.; Martinez-Vidal, F.; Oyanguren, A.; Rebollo De Miguel, M.; Ruiz Vidal, J.; Sanderswood, I. |
| Title |
Observation of Cabibbo-Suppressed Two-Body Hadronic Decays and Precision Mass Measurement of the Ω0c Baryon |
Type |
Journal Article |
| Year |
2024 |
Publication |
Physical Review Letters |
Abbreviated Journal |
Phys. Rev. Lett. |
| Volume |
132 |
Issue |
8 |
Pages |
081802 - 11pp |
| Keywords |
|
| Abstract |
The first observation of the singly Cabibbo-suppressed 0c -> -K thorn and 0c -> -z thorn decays is reported, using proton -proton collision data at a center -of -mass energy of 13 TeV, corresponding to an integrated luminosity of 5.4 fb-1, collected with the LHCb detector between 2016 and 2018. The branching fraction ratios are measured to be Bo0c ->-K thorn thorn Bo0c ->-z thorn thorn 1/4 1/26.08 ⠂ 0.51ostat thorn ⠂ 0.40osyst thorn ⠃%; Bo0c ->-z thorn thorn Bo0c ->-z thorn thorn 1/4 1/215.81 ⠂ 0.87ostat thorn ⠂ 0.44osyst thorn ⠂ 0.16oext thorn ⠃%. In addition, using the 0c -> -z thorn decay channel, the 0c baryon mass is measured to be Mo0c thorn 1/4 2695.28 ⠂ 0.07ostat thorn ⠂ 0.27osyst thorn ⠂ 0.30oext thorn MeV; improving the precision of the previous world average by a factor of 4. |
| Address |
[Leite, J. Baptista de Souza; Bediaga, I. B.; Torres, M. Cruz; Da Graca, U. De Freitas Carneiro; De Miranda, J. M.; dos Reis, A. C.; Falcao, L. N.; Gomes, A.; Massafferri, A.; Santoro, L.; Machado, D. Torres] CBPF, Rio De Janeiro, Brazil |
| 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 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:001190704700002 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
6053 |
| Permanent link to this record |
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| Author |
LHCb Collaboration (Aaij, R. et al); Jaimes Elles, S.J.; Jashal, B.K.; Martinez-Vidal, F.; Oyanguren, A.; Rebollo De Miguel, M.; Sanderswood, I.; Zhuo, J. |
| Title |
Curvature-bias corrections using a pseudomass method |
Type |
Journal Article |
| Year |
2024 |
Publication |
Journal of Instrumentation |
Abbreviated Journal |
J. Instrum. |
| Volume |
19 |
Issue |
3 |
Pages |
P03010 - 22pp |
| Keywords |
Analysis and statistical methods; Detector alignment and calibration methods (lasers, sources, particle-beams); Large detector-systems performance; Performance of High Energy Physics Detectors |
| Abstract |
Momentum measurements for very high momentum charged particles, such as muons from electroweak vector boson decays, are particularly susceptible to charge-dependent curvature biases that arise from misalignments of tracking detectors. Low momentum charged particles used in alignment procedures have limited sensitivity to coherent displacements of such detectors, and therefore are unable to fully constrain these misalignments to the precision necessary for studies of electroweak physics. Additional approaches are therefore required to understand and correct for these effects. In this paper the curvature biases present at the LHCb detector are studied using the pseudomass method in proton-proton collision data recorded at centre of mass energy root s = 13 TeV during 2016, 2017 and 2018. The biases are determined using Z -> mu(+)mu(-) decays in intervals defined by the data-taking period, magnet polarity and muon direction. Correcting for these biases, which are typically at the 10(-4) GeV-1 level, improves the Z -> mu(+)mu(-) mass resolution by roughly 18% and eliminates several pathological trends in the kinematic-dependence of the mean dimuon invariant mass. |
| Address |
[Egede, U.; Fujii, Y.; Hadavizadeh, T.; Henderson, R. D. L.; Lane, J. J.; Monk, M.; Song, R.; Walton, E. J.; Ward, J. A.] Monash Univ, Sch Phys & Astron, Melbourne, Vic, Australia, Email: seophine.stanislaus@cern.ch |
| Corporate Author |
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Thesis |
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| Publisher |
IOP Publishing Ltd |
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 |
1748-0221 |
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:001190907900003 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
6057 |
| Permanent link to this record |
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| Author |
LHCb Collaboration (Aaij, R. et al); Jaimes Elles, S.J.; Jashal, B.K.; Martinez-Vidal, F.; Oyanguren, A.; Rebollo De Miguel, M.; Sanderswood, I.; Zhuo, J. |
| Title |
Production of η and η' mesons in pp and pPb collisions |
Type |
Journal Article |
| Year |
2024 |
Publication |
Physical Review C |
Abbreviated Journal |
Phys. Rev. C |
| Volume |
109 |
Issue |
2 |
Pages |
024907 - 20pp |
| Keywords |
|
| Abstract |
The production of eta and eta' mesons is studied in proton -proton and proton -lead collisions collected with the LHCb detector. Proton -proton collisions are studied at center -of -mass energies of 5.02 and 13 TeV and proton -lead collisions are studied at a center -of -mass energy per nucleon of 8.16 TeV. The studies are performed in center -of -mass (c.m.) rapidity regions 2.5 < y(c.m.) < 3.5 (forward rapidity) and -4.0 < y(c.m.) < -3.0 (backward rapidity) defined relative to the proton beam direction. The eta and eta' production cross sections are measured differentially as a function of transverse momentum for 1.5 < p(T) < 10 GeV and 3 < p(T) < 10 GeV, respectively. The differential cross sections are used to calculate nuclear modification factors. The nuclear modification factors for eta and eta' mesons agree at both forward and backward rapidity, showing no significant evidence of mass dependence. The differential cross sections of eta mesons are also used to calculate eta/pi 0 cross-section ratios, which show evidence of a deviation from the world average. These studies offer new constraints on mass -dependent nuclear effects in heavy -ion collisions, as well as eta and eta' meson fragmentation. |
| Address |
[Egede, U.; Fujii, Y.; Hadavizadeh, T.; Henderson, R. D. L.; Lane, J. J.; Monk, M.; Song, R.; Walton, E. J.; Ward, J. A.] Monash Univ, Sch Phys & Astron, Melbourne, Vic, Australia, Email: seophine.stanislaus@cern.ch |
| 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 Issue |
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Edition |
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| ISSN |
2469-9985 |
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:001183159900011 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
6062 |
| Permanent link to this record |
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| Author |
LHCb Collaboration (Aaij, R. et al); Jaimes Elles, S.J.; Jashal, B.K.; Martinez-Vidal, F.; Oyanguren, A.; Rebollo De Miguel, M.; Sanderswood, I.; Zhuo, J. |
| Title |
Helium identification with LHCb |
Type |
Journal Article |
| Year |
2024 |
Publication |
Journal of Instrumentation |
Abbreviated Journal |
J. Instrum. |
| Volume |
19 |
Issue |
2 |
Pages |
P02010 - 23pp |
| Keywords |
dE/dx detectors; Ion identification systems; Large detector systems for particle and astroparticle physics; Particle identification methods |
| Abstract |
The identification of helium nuclei at LHCb is achieved using a method based on measurements of ionisation losses in the silicon sensors and timing measurements in the Outer Tracker drift tubes. The background from photon conversions is reduced using the RICH detectors and an isolation requirement. The method is developed using pp collision data at root s = 13 TeV recorded by the LHCb experiment in the years 2016 to 2018, corresponding to an integrated luminosity of 5.5 fb(-1). A total of around 10(5) helium and antihelium candidates are identified with negligible background contamination. The helium identification efficiency is estimated to be approximately 50% with a corresponding background rejection rate of up to O(10(12)). These results demonstrate the feasibility of a rich programme of measurements of QCD and astrophysics interest involving light nuclei. |
| Address |
[Egede, U.; Fujii, Y.; Hadavizadeh, T.; Henderson, R. D. L.; Lane, J. J.; Monk, M.; Song, R.; Walton, E. J.; Ward, J. A.] Monash Univ, Sch Phys & Astron, Melbourne, Vic, Australia, Email: rmoise@cern.ch |
| Corporate Author |
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Thesis |
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| Publisher |
IOP Publishing Ltd |
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 |
1748-0221 |
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:001185791500006 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
6068 |
| Permanent link to this record |
