Bottom quark energy loss and hadronization with B+ and $$ {\textrm{B}}_{\textrm{s}}^0 $$ nuclear modification factors using pp and PbPb collisions at $$ \sqrt{s_{\textrm{NN}}} $$ = 5.02 TeV

A bstract The production cross sections of $$ {\textrm{B}}_{\textrm{s}}^0 $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msubsup> <mml:mi>B</mml:mi> <mml:mi>s</mml:mi> <mml:mn>0</mml:mn> </mml:msubsup> </mml:math> and B + mesons are reported in proton-proton (pp) collisions recorded by the CMS experiment at the CERN LHC with a center-of-mass energy of 5.02 TeV. The data sample corresponds to an integrated luminosity of 302 pb − 1 . The cross sections are based on measurements of the $$ {\textrm{B}}_{\textrm{s}}^0 $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msubsup> <mml:mi>B</mml:mi> <mml:mi>s</mml:mi> <mml:mn>0</mml:mn> </mml:msubsup> </mml:math> → J /ψ ( μ + μ − ) ϕ (1020)(K + K − ) and B + → J /ψ ( μ + μ − )K + decay channels. Results are presented in the transverse momentum ( p T ) range 7–50 GeV /c and the rapidity interval | y | &lt; 2 . 4 for the B mesons. The measured p T -differential cross sections of B + and $$ {\textrm{B}}_{\textrm{s}}^0 $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msubsup> <mml:mi>B</mml:mi> <mml:mi>s</mml:mi> <mml:mn>0</mml:mn> </mml:msubsup> </mml:math> in pp collisions are well described by fixed-order plus next-to-leading logarithm perturbative quantum chromodynamics calculations. Using previous PbPb collision measurements at the same nucleon-nucleon center-of-mass energy, the nuclear modification factors, R AA , of the B mesons are determined. For p T &gt; 10 GeV /c , both mesons are found to be suppressed in PbPb collisions (with R AA values significantly below unity), with less suppression observed for the $$ {\textrm{B}}_{\textrm{s}}^0 $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msubsup> <mml:mi>B</mml:mi> <mml:mi>s</mml:mi> <mml:mn>0</mml:mn> </mml:msubsup> </mml:math> mesons. In this p T range, the R AA values for the B + mesons are consistent with those for inclusive charged hadrons and D 0 mesons. Below 10 GeV /c , both B + and $$ {\textrm{B}}_{\textrm{s}}^0 $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msubsup> <mml:mi>B</mml:mi> <mml:mi>s</mml:mi> <mml:mn>0</mml:mn> </mml:msubsup> </mml:math> are found to be less suppressed than either inclusive charged hadrons or D 0 mesons, with the $$ {\textrm{B}}_{\textrm{s}}^0 $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msubsup> <mml:mi>B</mml:mi> <mml:mi>s</mml:mi> <mml:mn>0</mml:mn> </mml:msubsup> </mml:math> R AA value consistent with unity. The R AA values found for the B + and $$ {\textrm{B}}_{\textrm{s}}^0 $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msubsup> <mml:mi>B</mml:mi> <mml:mi>s</mml:mi> <mml:mn>0</mml:mn> </mml:msubsup> </mml:math> are compared to theoretical calculations, providing constraints on the mechanism of bottom quark energy loss and hadronization in the quark-gluon plasma, the hot and dense matter created in ultrarelativistic heavy ion collisions.

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