Measurement of the production of charm jets tagged with D0 mesons in pp collisions at $$ \sqrt{\mathrm{s}}=7 $$ TeV

Abstract

A bstract The production of charm jets in proton-proton collisions at a center-of-mass energy of $$ \sqrt{s}=7 $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msqrt> <mml:mi>s</mml:mi> </mml:msqrt> <mml:mo>=</mml:mo> <mml:mn>7</mml:mn> </mml:math> TeV was measured with the ALICE detector at the CERN Large Hadron Collider. The measurement is based on a data sample corresponding to a total integrated luminosity of 6 . 23 nb −1 , collected using a minimum-bias trigger. Charm jets are identified by the presence of a D 0 meson among their constituents. The D 0 mesons are reconstructed from their hadronic decay D 0 →K − π + . The D 0 -meson tagged jets are reconstructed using tracks of charged particles (track-based jets) with the anti- k T algorithm in the jet transverse momentum range $$ 5&lt;{p}_{{\mathrm{T}}_{,\mathrm{jet}}}^{\mathrm{ch}} $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mn>5</mml:mn> <mml:mo>&lt;</mml:mo> <mml:msubsup> <mml:mi>p</mml:mi> <mml:msub> <mml:mi>T</mml:mi> <mml:mrow> <mml:mo>,</mml:mo> <mml:mi>jet</mml:mi> </mml:mrow> </mml:msub> <mml:mi>ch</mml:mi> </mml:msubsup> </mml:math> &lt; 30 GeV /c and pseudorapidity | η jet | &lt; 0 . 5. The fraction of charged jets containing a D 0 -meson increases with $$ {p}_{{\mathrm{T}}_{,\mathrm{jet}}}^{\mathrm{ch}} $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msubsup> <mml:mi>p</mml:mi> <mml:msub> <mml:mi>T</mml:mi> <mml:mrow> <mml:mo>,</mml:mo> <mml:mi>jet</mml:mi> </mml:mrow> </mml:msub> <mml:mi>ch</mml:mi> </mml:msubsup> </mml:math> from 0 . 042 ± 0 . 004 (stat) ± 0 . 006 (syst) to 0 . 080 ± 0 . 009 (stat) ± 0 . 008 (syst). The distribution of D 0 -meson tagged jets as a function of the jet momentum fraction carried by the D 0 meson in the direction of the jet axis $$ \left({z}_{\parallel}^{\mathrm{ch}}\right) $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mfenced> <mml:msubsup> <mml:mi>z</mml:mi> <mml:mo>∥</mml:mo> <mml:mi>ch</mml:mi> </mml:msubsup> </mml:mfenced> </mml:math> is reported for two ranges of jet transverse momenta, $$ 5&lt;{p}_{{\mathrm{T}}_{,\mathrm{jet}}}^{\mathrm{ch}} $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mn>5</mml:mn> <mml:mo>&lt;</mml:mo> <mml:msubsup> <mml:mi>p</mml:mi> <mml:msub> <mml:mi>T</mml:mi> <mml:mrow> <mml:mo>,</mml:mo> <mml:mi>jet</mml:mi> </mml:mrow> </mml:msub> <mml:mi>ch</mml:mi> </mml:msubsup> </mml:math> &lt; 15 GeV /c and $$ 15&lt;{p}_{{\mathrm{T}}_{,\mathrm{jet}}}^{\mathrm{ch}} $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mn>15</mml:mn> <mml:mo>&lt;</mml:mo> <mml:msubsup> <mml:mi>p</mml:mi> <mml:msub> <mml:mi>T</mml:mi> <mml:mrow> <mml:mo>,</mml:mo> <mml:mi>jet</mml:mi> </mml:mrow> </mml:msub> <mml:mi>ch</mml:mi> </mml:msubsup> </mml:math> &lt; 30 GeV /c in the intervals $$ 0.2&lt;{z}_{\Big\Vert}^{\mathrm{ch}}&lt;1.0 $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mn>0.2</mml:mn> <mml:mo>&lt;</mml:mo> <mml:msubsup> <mml:mi>z</mml:mi> <mml:mo>‖</mml:mo> <mml:mi>ch</mml:mi> </mml:msubsup> <mml:mo>&lt;</mml:mo> <mml:mn>1.0</mml:mn> </mml:math> and $$ 0.4&lt;{z}_{\Big\Vert}^{\mathrm{ch}}&lt;1.0 $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mn>0.4</mml:mn> <mml:mo>&lt;</mml:mo> <mml:msubsup> <mml:mi>z</mml:mi> <mml:mo>‖</mml:mo> <mml:mi>ch</mml:mi> </mml:msubsup> <mml:mo>&lt;</mml:mo> <mml:mn>1.0</mml:mn> </mml:math> , respectively. The data are compared with results from Monte Carlo event generators (PYTHIA 6, PYTHIA 8 and Herwig 7) and with a Next-to-Leading-Order perturbative Quantum Chromodynamics calculation, obtained with the POWHEG method and interfaced with PYTHIA 6 for the generation of the parton shower, fragmentation, hadronisation and underlying event.