Measurement of D0, D+, Ds + and D*+ production in fixed target 920 GeV proton–nucleus collisions

Abstract

Abstract. The inclusive production cross sections of the charmed mesons D 0 , D + , D + s and D * + have been measured in interactions of 920 GeV protons on C, Ti, and W targets with the HERA-B detector at the HERA storage ring. Differential cross sections as a function of transverse momentum and Feynman's x variable are given for the central rapidity region and for transverse momenta up to pT = 3.5 GeV/c. The atomic mass number dependence and the leading to non-leading particle production asymmetries are presented as well.

Combined analysis of charm-quark fragmentation-fraction measurements

“…First, the selection is limited to the measurements obtained in the collisions of high energy particle beams as it assures an absence of possible matter effects and the charm quark production mechanism in these environments is well understood. The measurements of charm-hadron production in proton-meson, proton-nucleon and nucleon-nucleon collisions [38][39][40][41][42][43] were omitted as those provide results in very specific production environment and energy ranges which cannot be easily compared to the results in other experiments.…”

Charm production in DPMJET

“…The best available measurements at the time were those from the LEBC hydrogen bubble chamber that took data at CERN and Fermilab during the late 1980s using proton beams of 400 GeV and 800 GeV, respectively [6,7]. Since then, a significant amount of new experiments have taken place, most notably in fixed target runs at Fermilab, but also using various types of colliders and most recently the HERA-B detector at DESY [8]. In this work, the version of DPMJET integrated in CORSIKA was used, running in first-interaction mode.…”

“…This is consistent with the value obtained from simulating charm production in DPMJET (9.5 μbarn/nucleon). Finally, the simulation was compared to data from HERA-B [8]. Even though the kinematic region covered by the detector was limited to −0.15 < x f < 0.05 and [6] and [7].…”

Measurement of the cross section of charmed hadrons and the nuclear dependence alpha

“…Muchos experimentos han medido la sección eficaz total de charm principalmente para los haces de protones y π, los experimentos con el haz de protones son NA32, NA27, E743, E653, E769, y HERA-B [1,2,3,4,5,6], respectivamente, los experimentos XXXVIII Introducción y Motivación para el haz de π son NA27 [7], NA32 [1,8], E653 [9], E769 [5], WA92 [10], y E791 [11], muchos de estos resultados son sólo para los mesones D (cargados y neutrales). Pero para obtener la sección eficaz total de charm además de sumar los valores obtenidos de los mesones D (neutrales y cargados), se tienen que tomar en cuenta la producción de otros hadrones con charm (D s , Λ c y otros bariones charm).…”

“…Estos experimentos son BIS-2 [15], WA82 [16], E769 [17,18], E789 [19], WA92 [10], E706 [20], y HERA-B [6], la mayoría de estos experimentos solamente publicaron un valor promedio para el parámetro α, aunque es importante señalar que 3 de estos experimentos muestran el parámetro α como función de x F y p t , estos son [16,17,10]. La mayoría de los valores son consistentes con α=1 [21].…”