Search for Vector-mediated Dark Matter at the LHC with Forward Proton Tagging

Abstract

We investigate the production of fermionic dark matter $\chi$ via $pp\to p\gamma p\to pj\chi \bar{\chi }X$ mediated by a leptophobic spin-1 particle, where one of the protons remains intact and is tagged by forward proton detectors. We find that the masses of $\chi$ and the mediator $Z^{\prime }$ are severely constrained when $Z^{\prime }$ interacts with $\chi$ and quarks through the vector couplings. We show that dark matter searches in this production channel are sensitive to a mediator mass $m_{Z^{\prime }}\lesssim 1.4\mathrm{TeV}$ at 14 TeV at the LHC with an integrated luminosity $L_{\mathrm{int}}=3000{\mathrm{fb}}^{-1}$. The lower mass bound on the dark matter is $m_{\chi }\simeq 550\mathrm{GeV}$ at the mediator mass $m_{Z^{\prime }}=1.2\mathrm{TeV}$.

Comments: 16 pages, 5 figures, 1 table, version to appear in PRD