Abstract
A method is proposed for determining the masses of the new particles N, X, Y, Z in collider events containing a pair of effectively identical decay chains Z → Y + jet, Y → X + l 1, X → N + l 2, where l 1, l 2 are opposite-sign same-flavour charged leptons and N is invisible. By first determining the upper edge of the dilepton invariant mass spectrum, we reduce the problem to a curve for each event in the 3-dimensional space of mass-squared differences. The region through which most curves pass then determines the unknown masses. A statistical approach is applied to take account of mismeasurement of jet and missing momenta. The method is easily visualized and rather robust against combinatorial ambiguities and finite detector resolution. It can be successful even for small event samples, since it makes full use of the kinematical information from every event.
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References
A.J. Barr and C.G. Lester, A review of the mass measurement techniques proposed for the Large Hadron Collider, arXiv:1004.2732 [SPIRES].
H.-C. Cheng, D. Engelhardt, J.F. Gunion, Z. Han and B. McElrath, Accurate mass determinations in decay chains with missing energy, Phys. Rev. Lett. 100 (2008) 252001 [arXiv:0802.4290] [SPIRES].
H.-C. Cheng, J.F. Gunion, Z. Han and B. McElrath, Accurate mass determinations in decay chains with missing energy: II, Phys. Rev. D 80 (2009) 035020 [arXiv:0905.1344] [SPIRES].
K. Kawagoe, M.M. Nojiri and G. Polesello, A new SUSY mass reconstruction method at the CERN LHC, Phys. Rev. D 71 (2005) 035008 [hep-ph/0410160] [SPIRES];
M.M. Nojiri, G. Polesello and D.R. Tovey, A hybrid method for determining SUSY particle masses at the LHC with fully identified cascade decays, JHEP 05 (2008) 014 [arXiv:0712.2718] [SPIRES].
B. Webber, Mass determination in sequential particle decay chains, JHEP 09 (2009) 124 [arXiv:0907.5307] [SPIRES].
B.C. Allanach et al., The Snowmass points and slopes: Benchmarks for SUSY searches, in the proceedings of the APS/DPF/DPB Summer Study on the Future of Particle Physics (Snowmass2001), N. Graf ed., Eur. Phys. J. C 25 (2002) 113 [hep-ph/0202233] [SPIRES].
G. Corcella et al., HERWIG 6.5: an event generator for Hadron Emission Reactions With Interfering Gluons (including supersymmetric processes), JHEP 01 (2001) 010 [hep-ph/0011363] [SPIRES].
G. Corcella et al., HERWIG 6.5 release note, hep-ph/0210213 [SPIRES].
S. Moretti, K. Odagiri, P. Richardson, M.H. Seymour and B.R. Webber, Implementation of supersymmetric processes in the HERWIG event generator, JHEP 04 (2002) 028 [hep-ph/0204123] [SPIRES].
E. Richter-Was, AcerDET: A particle level fast simulation and reconstruction package for phenomenological studies on high p T physics at LHC, hep-ph/0207355 [SPIRES].
CMS collaboration, G.L. Bayatian et al., CMS technical design report, volume II: physics performance, J. Phys. G 34 (2007) 995 [SPIRES].
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ArXiv ePrint: 1005.2532
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Nojiri, M.M., Sakurai, K. & Webber, B.R. Reconstructing particle masses from pairs of decay chains. J. High Energ. Phys. 2010, 69 (2010). https://doi.org/10.1007/JHEP06(2010)069
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DOI: https://doi.org/10.1007/JHEP06(2010)069