Discovery potential of stable and near-threshold doubly heavy tetraquarks at the LHC

Ahmed Ali,Qin Qin,Wei Wang

doi:10.1016/j.physletb.2018.09.018

Abstract

We study the LHC discovery potential of the double-bottom tetraquarks bbu¯d¯, bbu¯s¯ and bbd¯s¯, the lightest of which having JP=1+, called T[u¯d¯]{bb}, T[u¯s¯]{bb} and T[d¯s¯]{bb}, are expected to be stable against strong decays. Employing the Monte Carlo generators MadGraph5_aMC@NLO and Pythia6, we simulate the process pp→b¯bb¯b+X and calculate the bb-diquark jet configurations, specified by the invariant mass interval Mbb<MT[q¯q¯′]{bb}+ΔM. Estimates of ΔM from the measured product σ(pp→Bc++X)B(Bc+→J/ψπ+) are presented and used to get the bb-diquark jet cross sections in double-bottom hadrons σ(pp→H{bb}+X), where H{bb} represent tetraquarks and baryons. This is combined with the LHCb data on the fragmentation b→Λb and b→B to obtain σ(pp→T[u¯d¯]{bb}+X)=(2.8−0.7+1.0)nb at s=13 TeV, and about a quarter of this for the T[u¯s¯]{bb} and T[d¯s¯]{bb}, each. We also present estimates of the production cross sections for the mixed bottom-charm tetraquarks, bcu¯d¯, bcu¯s¯ and bcd¯s¯, obtaining σ(pp→T[u¯d¯][bc]+X)=(103−25+39)nb at s=13 TeV, and the related ones having T[u¯s¯][bc] and T[d¯s¯][bc]. They have excellent discovery potential at the LHC, as their branching ratios in various charge combinations of BD(s)(γ) are anticipated to be large.

Highlights

The discovery of X(3872), followed by well over a dozen related mesonic states, X, Y, Z, and two baryonic states Pc(4380) and Pc(4450), has opened a second layer of “extraordinary” hadrons in QCD, containing four and five valence quarks and antiquarks [1]
The competing theoretical models put forward can be roughly classified into two categories: those reflecting the residual QCD long-distance effects, dominated by meson exchanges, and those reflecting genuine short-distance interactions, dominated by gluon exchanges
Heavy tetraquarks (DHTQ) Q i Q jqkqmust exist in the Heavy Quark Symmetry (HQS) limit

Summary

Contents lists available at ScienceDirect

Discovery potential of stable and near-threshold doubly heavy tetraquarks at the LHC. Ahmed Ali a,∗, Qin Qin b, Wei Wang c a Deutsches Elektronen-Synchrotron DESY, D-22607 Hamburg, Germany b Theoretische Physik 1, Naturwissenschaftlich-Technische Fakultät, Universität Siegen, Walter-Flex-Strasse 3, D-57068 Siegen, Germany c INPAC, Shanghai Key Laboratory for Particle Physics and Cosmology, MOE Key Laboratory for Particle Physics, School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China article info. Article history: Received 3 July 2018 Received in revised form 17 August 2018 Accepted 11 September 2018 Available online 14 September 2018 Editor: A. We study the LHC discovery potential of the double-bottom tetraquarks bbud, bbus ̄ and bbds ̄, the lightest of which having. Are presented and used to get the bb-diquark jet cross sections in double-bottom hadrons σ We present estimates of the production cross sections for the mixed bottom-charm tetraquarks, bcud ̄, bcus ̄. Excellent discovery (103+−3295 ) potential nb at the LHC, as their branching ratios in various charge combinations of B D(s)(γ ) are anticipated to be large

Introduction

GeV y