Dark Matter Searches in Jet plus Missing Energy in $\rm γp$ collision at CERN LHC

TL;DR

This work investigates dark matter production in γp photoproduction at the LHC, focusing on the jet plus missing energy signature from pp → pγp → pχχj within a model-independent EFT framework. Using the Equivalent Photon Approximation and forward proton detectors, the authors compute photoproduction cross sections with photon and parton luminosities, including Single Diffractive backgrounds, and perform a cut-based analysis with realistic detector acceptances. For Mχ = 10 GeV and L = 200 fb−1, they obtain 5σ bounds on the DM–quark interaction scale ΛD5 up to 665.5, 808.9, and 564.0 GeV for ξ1, ξ2, and ξ3 respectively, with a ~1 TeV reach at 3σ for ξ2; these bounds are competitive with LEP-2 and comparable to some e+e− collider projections. The study highlights the potential of γp processes with forward tagging to complement standard pp searches and discusses EFT validity and pileup considerations as luminosity increases.

Abstract

In this paper, we investigate the $\rm γp$ photoproduction of jet plus missing energy signal to set limits on the couplings of the fermionic dark matter to the quarks at the LHC via the main reaction $\rm pp\rightarrow pγp\rightarrow p χχj$. We assume a typical LHC multipurpose forward detectors and work in a model independent Effective Field Theory framework. Typically, when we do the background analysis, we also include their corresponding Single Diffractive (SD) productions. Our result shows that by requiring a $5σ$ ($\rm S/\sqrt{B} \geq 5$) signal deviation, with an integrated luminosity of $\rm {\cal L} = 200 fb^{-1}$, the lower bounds of WIMP masses scale can be detected up to $\rm Λ$ equal 665.5, 808.9 and 564.0 GeV for the forward detector acceptances $ξ_1$, $ξ_2$, and $ξ_3$, respectively, where $0.0015<ξ_1<0.5$, $0.1<ξ_2<0.5$ and $0.0015<ξ_3<0.15$.

Figures (7)

• Figure 1: A generic diagram for the photoproduction of $\rm pp\rightarrow p\gamma p\rightarrow pXY$ at the CERN LHC.
• Figure 2: Parton level Feynman diagrams for $\rm pp\rightarrow p\gamma p\rightarrow p \chi\chi j$ include the s-channel contribution (1) and the t-channel contribution (2). Here q=u, d, c, s, b, $\bar{u}$, $\bar{d}$, $\bar{c}$, $\bar{s}$ and $\bar{b}$. Black blobs represent the $\rm \chi\chi q q$ couplings parameterized by Eq.(\ref{['LEFTDM']}).
• Figure 3: Feynman diagrams for $\rm \gamma p$ collision of the SM production of Z+jet where Z decays into a pair of neutrinos and W+jet associated production with the W decays into a neutrino and a charged lepton falls outside the acceptance range of the detector..
• Figure 4: Some Feynman diagrams for Single Diffractive production of Z+jet where Z decays into a pair of neutrinos and W+jet associated production with the W decays into a neutrino and a charged lepton falls outside the acceptance range of the detector.
• Figure 5: The signal and background differential cross sections of the transverse momentum of the jet ($\rm p^{jet}_T$), the invariant mass of the produced System ($\rm M_{inv}$) and the $\rm H_T$ distributions for $\rm pp\rightarrow p\gamma p\rightarrow p \chi\chi j$. The Basic kinematic cuts and survival probability factor are taken into account. The forward detector acceptance is chosen to be $0.0015<\xi_1<0.5$. Here $\rm M_\chi=10GeV$ and $\rm \Lambda_{D5}=100$ and 200 GeV.