Probing the existence of a new charged vector boson decaying into heavy neutral leptons using ultra-peripheral heavy ion collisions at ATLAS

Abstract In this paper we explore the potential of Ultra-peripheral Collisions at the LHC to investigate new physics, focusing on the production of new charged vector bosons $${V}^{\pm }$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msup> <mml:mrow> <mml:mi>V</mml:mi> </mml:mrow> <mml:mo>±</mml:mo> </mml:msup> </mml:math> that decay into heavy neutral leptons $$N_{L}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mi>N</mml:mi> <mml:mi>L</mml:mi> </mml:msub> </mml:math> in the context of the Vector Scotogenic Model. We show that the ATLAS experiment, searching for dilepton+met final states via UPCs of lead ions, can directly probe the existence of new charged vector bosons in the 5 GeV $$&lt;M_{V^{\pm }}, M_{N_L}&lt;$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mo>&lt;</mml:mo> <mml:msub> <mml:mi>M</mml:mi> <mml:msup> <mml:mi>V</mml:mi> <mml:mo>±</mml:mo> </mml:msup> </mml:msub> <mml:mo>,</mml:mo> <mml:msub> <mml:mi>M</mml:mi> <mml:msub> <mml:mi>N</mml:mi> <mml:mi>L</mml:mi> </mml:msub> </mml:msub> <mml:mo>&lt;</mml:mo> </mml:mrow> </mml:math> 105 GeV mass range. Our analysis identifies regions in the parameter space where the signal can be distinguished from the background with high statistical significance. Within this mass range, ATLAS can exclude at 95% CL specific ( $${M}_{{V}^{\pm }}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mi>M</mml:mi> <mml:msup> <mml:mrow> <mml:mi>V</mml:mi> </mml:mrow> <mml:mo>±</mml:mo> </mml:msup> </mml:msub> </mml:math> , $${M}_{{N}_{L}}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mi>M</mml:mi> <mml:msub> <mml:mi>N</mml:mi> <mml:mi>L</mml:mi> </mml:msub> </mml:msub> </mml:math> ) mass scenarios such as (30 GeV, 20 GeV), (30 GeV, 10 GeV) and (20 GeV, 10 GeV). In a discovery scenario, ATLAS could reach a significance of 5 $$\sigma $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>σ</mml:mi> </mml:math> for (20 GeV, 10 GeV). In addition, we show that HL-LHC with proton–proton UPCs could explore higher mass ranges, specifically 100 GeV $$&lt; M_{V^{\pm }}, M_{N_L}&lt;$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mo>&lt;</mml:mo> <mml:msub> <mml:mi>M</mml:mi> <mml:msup> <mml:mi>V</mml:mi> <mml:mo>±</mml:mo> </mml:msup> </mml:msub> <mml:mo>,</mml:mo> <mml:msub> <mml:mi>M</mml:mi> <mml:msub> <mml:mi>N</mml:mi> <mml:mi>L</mml:mi> </mml:msub> </mml:msub> <mml:mo>&lt;</mml:mo> </mml:mrow> </mml:math> 350 GeV. We find that the HL-LHC can exclude this mass range with 95% CL, covering a larger parameter space than previous SUSY searches, and most scenarios can achieve a discovery significance of 5 $$\sigma $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>σ</mml:mi> </mml:math> .