Deployment of a Matrix Element Method code for the ttH channel analysis on GPU’s platform

¹ Laboratoire Leprince-Ringuet, Ecole polytechnique, Palaiseau, France
² Laboratoire Leprince-Ringuet, Ecole polytechnique, Palaiseau, France. Now at Centre de Physique des Particules de Marseille, Aix-Marseille Université, CNRS/IN2P3, Marseille, France
³ GENCI “Grand Equipement de Calcul Intensif”, 6 bis rue Auguste Vitu, Paris, France

^* e-mail: grasseau@llr.in2p3.fr
^** e-mail: beaudette@llr.in2p3.fr
^*** e-mail: mperez@llr.in2p3.fr
^**** e-mail: zabi@cern.ch
^† e-mail: chiron@llr.in2p3.fr
^‡ e-mail: thomas.strebler@cern.ch
^§ e-mail: hautreux@genci.fr

Published online: 17 September 2019

Abstract

The observation of the associated production of the Higgs boson with two top quarks in proton-proton collisions is one of the highlights of the LHC Run 2. Driven by the theoretical description of the physics processes, the Matrix Element Method (MEM) consists in computing a probability that an event is compatible with the signal hypothesis (ttH) or with one of the background hypotheses. It is a powerful classifying tool requiring high dimensional integral computations. The deployment of our MEM production code on GPU’s platform will be described. What follows will focus on the adaptation of the main components of the computations in OpenCL kernels, namely the Magraph matrix element code generator, VEGAS, and LHAPDF. Finally, the gain obtained on GPU’s platforms compared with classical CPU’s platforms will be assessed.