\sqrt{s}_min: a global inclusive variable for determining the mass scale of new physics in events with missing energy at hadron colliders

Abstract

We propose a new global and fully inclusive variable \sqrt{s}_{min} for determining the mass scale of new particles in events with missing energy at hadron colliders. We define \sqrt{s}_{min} as the minimum center-of-mass parton level energy consistent with the measured values of the total calorimeter energy E and the total visible momentum \vec{P}. We prove that for an arbitrary event, \sqrt{s}_{min} is simply given by the formula \sqrt{s}_{min}=\sqrt{E^2-P_z^2}+\sqrt{\met^2+M_{inv}^2}, where M_{inv} is the total mass of all invisible particles produced in the event. We use t\bar{t} production and several supersymmetry examples to argue that the peak in the \sqrt{s}_{min} distribution is correlated with the mass threshold of the parent particles originally produced in the event. This conjecture allows a determination of the heavy superpartner mass scale (as a function of the LSP mass) in a completely general and model-independent way, and without the need for any exclusive event reconstruction. In our SUSY examples of several multijet plus missing energy signals, the accuracy of the mass measurement based on \sqrt{s}_{min} is typically at the percent level, and never worse than 10%. After including the effects of initial state radiation and multiple parton interactions, the precision gets worse, but for heavy SUSY mass spectra remains 10%.

33 pages, 36 figures, discussion on effect of ISR and MPI added

References in corpus (25)

• PYTHIA 6.4 Physics and Manual
• Gluino Stransverse Mass
• Measuring superparticle masses at hadron collider using the transverse mass kink
• Minimal Kinematic Constraints and MT2
• On measuring the masses of pair-produced semi-invisibly decaying particles at hadron colliders
• Model-Independent Jets plus Missing Energy Searches
• Accurate Mass Determinations in Decay Chains with Missing Energy
• MTGEN : Mass scale measurements in pair-production at colliders
• Distinguishing Spins in Decay Chains at the Large Hadron Collider
• Transverse Observables and Mass Determination at Hadron Colliders
• Hunting for the Top Partner in the Littlest Higgs Model with T-parity at the LHC
• A Supersymmetric U(1)' Model with Multiple Dark Matters
• Mass Determination of New States at Hadron Colliders
• Inclusive transverse mass analysis for squark and gluino mass determination
• Handling jets + missing E_T channel using inclusive mT2
• The Precision Determination of Invisible-Particle Masses at the LHC
• A General Method for Model-Independent Measurements of Particle Spins, Couplings and Mixing Angles in Cascade Decays with Missing Energy at Hadron Colliders
• Missing energy look-alikes with 100 pb-1 at the LHC
• A short comparison between m_T2 and m_CT
• Study of the top reconstruction in top-partner events at the LHC
• A hybrid method for determining particle masses at the Large Hadron Collider with fully identified cascade decays
• Constrained invariant mass distributions in cascade decays. The shape of the "$m_{qll}$-threshold" and similar distributions
• Measuring the top quark mass with m_T2 at the LHC
• Mass Determination in Cascade Decays Using Shape Formulas
• Common gauge origin of discrete symmetries in observable sector and hidden sector

Cited by in corpus (7)

• A Review of the Mass Measurement Techniques proposed for the Large Hadron Collider
• Using kinematic boundary lines for particle mass measurements and disambiguation in SUSY-like events with missing energy
• Precise reconstruction of sparticle masses without ambiguities
• RECO level \sqrt{s}_{min} and subsystem \sqrt{s}_{min}: improved global inclusive variables for measuring the new physics mass scale in missing energy events at hadron colliders
• Mass determination in sequential particle decay chains
• Effects of QCD radiation on inclusive variables for determining the scale of new physics at hadron colliders
• Controlling ISR in sparticle mass reconstruction