The production of beauty hadrons was measured via semi-leptonic decays at mid-rapidity with the ALICE detector at the LHC in the transverse momentum interval 1< pT< 8 GeV/c in minimum-bias p-Pb collisions at sNN=5.02 TeV and in 1.3< pT< 8 GeV/c in the 20% most central Pb-Pb collisions at sNN=2.76 TeV. The pp reference spectra at s=5.02 TeV and s=2.76 TeV, needed for the calculation of the nuclear modification factors RpPb and RPbPb, were obtained by a pQCD-driven scaling of the cross section of electrons from beauty-hadron decays measured at s=7 TeV. The RPbPb is about 0.7 with an uncertainty of about 30% in the interval 3< pT< 6 GeV/c and 0.47 with an uncertainty of 25% in 6< pT< 8 GeV/c in Pb-Pb collisions. Below pT=3 GeV/c, the RPbPb values increase with decreasing transverse momentum with systematic uncertainties of 30-45%. The RpPb is consistent with unity within systematic uncertainties of about 20% at high pT, increasing at low pT, and is well described by theoretical calculations that include cold nuclear matter effects in p-Pb collisions. The measured RpPb and these calculations indicate that cold nuclear matter effects are small at high transverse momentum also in Pb-Pb collisions. Therefore, the observed reduction of RPbPb below unity for high pT can be ascribed to an effect of the hot and dense medium formed in Pb-Pb collisions.

Measurement of electrons from beauty-hadron decays in p-Pb collisions at √s_NN=5.02 TeV and Pb-Pb collisions at √s_NN=2.76 TeV / Adam, J., Adamová, D., Aggarwal, M.M., Aglieri Rinella, G., Agnello, M., Agrawal, N., Ahammed, Z., Ahmad, S., Ahn, S.U., Aiola, S., Akindinov, A., Alam, S.N., Albuquerque, D.S.D., Aleksandrov, D., Alessandro, B., Alexandre, D., Alfaro Molina, R., Alici, A., Alkin, A., Alme, J., et al.. - In: JOURNAL OF HIGH ENERGY PHYSICS. - ISSN 1029-8479. - STAMPA. - 7:(2017). [10.1007/JHEP07(2017)052]

Measurement of electrons from beauty-hadron decays in p-Pb collisions at √s_NN=5.02 TeV and Pb-Pb collisions at √s_NN=2.76 TeV

G. E. Bruno;
2017

Abstract

The production of beauty hadrons was measured via semi-leptonic decays at mid-rapidity with the ALICE detector at the LHC in the transverse momentum interval 1< pT< 8 GeV/c in minimum-bias p-Pb collisions at sNN=5.02 TeV and in 1.3< pT< 8 GeV/c in the 20% most central Pb-Pb collisions at sNN=2.76 TeV. The pp reference spectra at s=5.02 TeV and s=2.76 TeV, needed for the calculation of the nuclear modification factors RpPb and RPbPb, were obtained by a pQCD-driven scaling of the cross section of electrons from beauty-hadron decays measured at s=7 TeV. The RPbPb is about 0.7 with an uncertainty of about 30% in the interval 3< pT< 6 GeV/c and 0.47 with an uncertainty of 25% in 6< pT< 8 GeV/c in Pb-Pb collisions. Below pT=3 GeV/c, the RPbPb values increase with decreasing transverse momentum with systematic uncertainties of 30-45%. The RpPb is consistent with unity within systematic uncertainties of about 20% at high pT, increasing at low pT, and is well described by theoretical calculations that include cold nuclear matter effects in p-Pb collisions. The measured RpPb and these calculations indicate that cold nuclear matter effects are small at high transverse momentum also in Pb-Pb collisions. Therefore, the observed reduction of RPbPb below unity for high pT can be ascribed to an effect of the hot and dense medium formed in Pb-Pb collisions.
2017
Measurement of electrons from beauty-hadron decays in p-Pb collisions at √s_NN=5.02 TeV and Pb-Pb collisions at √s_NN=2.76 TeV / Adam, J., Adamová, D., Aggarwal, M.M., Aglieri Rinella, G., Agnello, M., Agrawal, N., Ahammed, Z., Ahmad, S., Ahn, S.U., Aiola, S., Akindinov, A., Alam, S.N., Albuquerque, D.S.D., Aleksandrov, D., Alessandro, B., Alexandre, D., Alfaro Molina, R., Alici, A., Alkin, A., Alme, J., et al.. - In: JOURNAL OF HIGH ENERGY PHYSICS. - ISSN 1029-8479. - STAMPA. - 7:(2017). [10.1007/JHEP07(2017)052]
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11589/122585
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