W boson studies in pPb and PbPb collisions with CMS

Hot Quarks 2014: Workshop for young scientists on the physics of ultrarelativistic nucleus-nucleus collisions

Chapon, Émilien^1

Laboratoire Leprince-Ringuet, École Polytechnique, Palaiseau cedex

91128, France^1

关键词: Center-of-mass energies;    Charge asymmetries;    Electron channel;    Electroweak bosons;    Nuclear collisions;    Parton distributions;    Pb-Pb collisions;    Strong interaction;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/612/1/012002/pdf
DOI  :  10.1088/1742-6596/612/1/012002

来源: IOP

【 摘 要 】

The electroweak W bosons do not participate in the strong interaction, and thus constitute clean probes of the initial state of nuclear collisions. They provide a unique constraint on the nuclear parton distributions, in particular on the antiquarks from the sea. A first analysis of PbPb data has confirmed the medium-blind characteristic of the electroweak bosons. With the new pPb data collected at the beginning of 2013, nuclear matter without the creation of a hot medium can hence be studied. Being 10 times more prevalent than Z bosons, the yield of W bosons recorded from pPb collisions allows precise comparisons to theoretical predictions. A yield of approximately 20 000 W is observed in pPb collisions in both the muon and electron channels. In this paper the CMS measurements of W bosons in PbPb at nucleon-nucleon center-of-mass energy of √sNN= 2:76 TeV and from the new pPb data at √sNN= 5:02 TeV are reported. The charge asymmetry, forward/backward asymmetry and fully corrected yields will be shown.