Measuring Masses in Semi-Invisible Final States at Electron-Positron Colliders

Abstract

Mass measurement of a particle whose decay products including invisible particles is a challenging task at colliders. For a new physics model involving a dark matter candidate $N$ and a $Z_2$ symmetry that stabilizes it, a typical new process at $e^{+}{e}^{-}$ colliders is the pair production $e^{+}{e}^{-}\to Y\bar{Y}$ followed by decay processes $Y\to aN$ and $\bar{Y}\to b\bar{N}$, where $a$ and $b$ are visible but $N$ is invisible. In this work, we propose a new method to measure the physical masses in this topology by making use of the kinematic equations given by momentum-energy conservation and on-shell conditions. For each event, the solvability of these equations determines a limited region on the trial $m_Y$-$m_N$ plane. The edge of this region can be used to define two variables, $m_Y^{\mathrm{edge}}$ and $m_N^{\mathrm{edge}}$, whose distributions are utilized to derive the measurement values of $m_Y$ and $m_N$. The measurement deviations and uncertainties are also estimated after including detector effects and background contamination.

23 pages, 15 figures, 2 tables. V2, method improved, figures and discussions added

References in corpus (28)

• Observation of a new particle in the search for the Standard Model Higgs boson with the ATLAS detector at the LHC
• Observation of a new boson at a mass of 125 GeV with the CMS experiment at the LHC
• The automated computation of tree-level and next-to-leading order differential cross sections, and their matching to parton shower simulations
• Gluino Stransverse Mass
• Using Subsystem MT2 for Complete Mass Determinations in Decay Chains with Missing Energy at Hadron Colliders
• Minimal Kinematic Constraints and MT2
• Central Exclusive Particle Production at High Energy Hadron Colliders
• On measuring the masses of pair-produced semi-invisibly decaying particles at hadron colliders
• Accurate Mass Determinations in Decay Chains with Missing Energy
• A Review of the Mass Measurement Techniques proposed for the Large Hadron Collider
• M_T2-assisted on-shell reconstruction of missing momenta and its application to spin measurement at the LHC
• MTGEN : Mass scale measurements in pair-production at colliders
• Transverse Observables and Mass Determination at Hadron Colliders
• Mass Determination of New States at Hadron Colliders
• \sqrt{s}_min: a global inclusive variable for determining the mass scale of new physics in events with missing energy at hadron colliders
• 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
• 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
• A hybrid method for determining particle masses at the Large Hadron Collider with fully identified cascade decays
• OPTIMASS: A Package for the Minimization of Kinematic Mass Functions with Constraints
• Mass reconstruction with $M_2$ under constraint in semi-invisible production at a hadron collider
• Measuring a Light Neutralino Mass at the ILC: Testing the MSSM Neutralino Cold Dark Matter Model
• Reconstructing semi-invisible events in resonant tau pair production from Higgs
• Constrained $\sqrt{{\hat{S}}_{min}}$ and reconstructing with semi-invisible production at hadron colliders
• Determining the Dark Matter Particle Mass through Antler Topology Processes at Lepton Colliders
• Energy spectra of massive two-body decay products and mass measurement
• Identifying the production process of new physics at colliders; symmetric or asymmetric?

Cited by in corpus (5)

• Probing dark matter particles at CEPC
• Exploring Fermionic Dark Matter via Higgs Boson Precision Measurements at the Circular Electron Positron Collider
• Exploring properties of long-lived particles in inelastic dark matter models at Belle II
• Singularity Variables for Missing Energy Event Kinematics
• New method for non-standard invisible particle searches in tau lepton decays