Probing Hidden Sectors with a muon beam: Total and differential cross-sections for vector boson production in muon bremsstrahlung

Abstract

Vector bosons, such as Dark Photon $A^{\prime }$ or $Z^{\prime }$, can couple to muons and be produced in the bremsstrahlung reaction ${\mu }^{-}+N\to {\mu }^{-}+N+A^{\prime }(Z^{\prime })$. Their possible subsequent invisible decay can be detected in fixed target experiments through missing energy/momentum signature. In such experiments, not only is the energy transfer to $A^{\prime }(Z^{\prime })$ important, but also the recoil muon angle ${\psi }_{{\mu }^{\prime }}$. In this paper, we derive the total and the double differential cross-sections involved in this process using the phase space Weiszäcker-Williams and improved Weiszäcker-Williams approximations, as well as using exact-tree-level calculations. As an example, we compare the derived cross-sections and resulting signal yields in the NA64$\mu$ experiment that uses a 160 GeV muon beam at the CERN Super Proton Synchrotron accelerator. We also discuss its impact on the NA64$\mu$ expected sensitivity to explore the $(g-2{)}_{\mu }$ anomaly favoured region with a $Z^{\prime }$ boson considering $10^{12}$ muons accumulated on target.

References in corpus (4)

• Measurement of the Positive Muon Anomalous Magnetic Moment to 0.46 ppm
• New Fixed-Target Experiments to Search for Dark Gauge Forces
• Muon g-2 and searches for a new leptophobic sub-GeV dark boson in a missing-energy experiment at CERN
• The Validity of the Weizsacker-Williams Approximation and the Analysis of Beam Dump Experiments: Production of a New Scalar Boson

Cited by in corpus (8)

• Prospects in the search for a new light $Z^{\prime }$ boson with the NA64$\mu$ experiment at the CERN SPS
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• Search for a light muon-philic $Z^{\prime }$ with the NA64-$e$ experiment at CERN
• Searching for Muonphilic Dark Sectors with Proton Beams
• Passage of millicharged particles in the electron beam-dump: refining constraints from SLACmQ and estimating sensitivity of NA64e
• Leptonic scalar portal: Origin of muon $g-2$ anomaly and dark matter?
• Probing hidden spin-2 mediator of dark matter with NA64e, LDMX, NA64$\mu$ and M${}^3$
• Leptophilic Gauge Bosons at Lepton Beam Dump Experiments