Production of heavy charged particles in proton-proton ultraperipheral collisions at the Large Hadron Collider: survival factor

S I Godunov,A N Rozanov,V A Novikov,E V Zhemchugov,M I Vysotsky

doi:10.1007/jhep10(2021)234

Abstract

Ultraperipheral collisions of high energy protons are a source of approximately real photons colliding with each other. Photon fusion can result in production of yet unknown charged particles in very clean events. The cleanliness of such an event is due to the requirement that the protons survive during the collision. Finite sizes of the protons reduce the probability of such outcome compared to point-like particles. We calculate the survival factors and cross sections for the production of heavy charged particles at the Large Hadron Collider.

Highlights

JHEP10(2021)234 of (ΛQCD/mZ)2 ∼ 10−6 as soon as we demand that the proton remains intact after emitting the Z boson
Our calculations have shown that the magnetic form factor contribution to the photon-photon luminosity is at the same order of magnitude as the survival factor contribution, so we keep it in the following
In ref. [36] we propose a model-independent approach to the search of charged heavy long-lived particles produced in ultraperipheral collisions at the LHC

Summary

EPA and the survival factor

The spectrum of equivalent photons of a proton with the Lorentz factor γ is [17,18,19]. Where σ(γγ → X) is the X production cross section in photon fusion, and P (b) is the probability for the protons to survive in a collision with the impact parameter b = |b1 − b2|. When the non-electromagnetic interactions between the protons are neglected, P (b) = 1, and the luminosities can be expressed through the integrated spectrum (2.3): Note that in this case the luminosities for different polarizations are equal, so one can use the simpler formula with σ(γγ When the dependence of the γγ → X cross section on the relative polarization of the photons is neglected, one gets the following expression for the survival factor:. In the case of the production of a pair of charged fermions with the mass m, eqs. (2.22), (2.23) are valid for s m2, see eq (3.1)

Production of heavy charged particles

Comparison to the experimental data

Findings

Conclusion