Abstract
We investigate spin correlation effects in the “antler” event topology pp → A(A*) → B 1 B 2 → (ℓ − C 1)(ℓ + C 2) at the LHC. We study the shapes of several kinematic variables, including the relative pseudorapidity, relative azimuthal angle and the energies of the two leptons, as well as several mass variables M ℓℓ , M eff, \( \sqrt {{{{s}_{{\min }}}}} \), M T2, M CT and M CTx . We focus on the two kinematic extremes of \(\sqrt{S}\) — threshold and infinity — and derive analytical expressions for the differential distributions of several variables, most notably the cos \(\theta_{{\ell -\ell +}}^{*}\) variable proposed by Barr in hep-ph/0511115. For all possible spin assignments of particles A, B and C, we derive the cos \(\theta_{{\ell -\ell +}}^{*}\) differential distribution at threshold, including the effects of spin correlations. Our analytical results help identify the problematic cases for spin discrimination.
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A.J. Barr and C.G. Lester, A review of the mass measurement techniques proposed for the large hadron collider, J. Phys. G 37 (2010) 123001 [arXiv:1004.2732] [INSPIRE].
A. Barr, T. Khoo, P. Konar, K. Kong, C. Lester, et al., Guide to transverse projections and mass-constraining variables, Phys. Rev. D 84 (2011) 095031 [arXiv:1105.2977] [INSPIRE].
A. Barr, Determining the spin of supersymmetric particles at the LHC using lepton charge asymmetry, Phys. Lett. B 596 (2004) 205 [hep-ph/0405052] [INSPIRE].
M. Battaglia, A. Datta, A. De Roeck, K. Kong and K.T. Matchev, Contrasting supersymmetry and universal extra dimensions at the CLIC multi-TeV e + e − collider, JHEP 07 (2005) 033 [hep-ph/0502041] [INSPIRE].
J.M. Smillie and B.R. Webber, Distinguishing spins in supersymmetric and universal extra dimension models at the large hadron collider, JHEP 10 (2005) 069 [hep-ph/0507170] [INSPIRE].
A. Datta, K. Kong and K.T. Matchev, Discrimination of supersymmetry and universal extra dimensions at hadron colliders, Phys. Rev. D 72 (2005) 096006 [Erratum ibid. D 72 (2005) 119901] [hep-ph/0509246] [INSPIRE].
A. Datta, G.L. Kane and M. Toharia, Is it SUSY?, hep-ph/0510204 [INSPIRE].
A. Barr, Measuring slepton spin at the LHC, JHEP 02 (2006) 042 [hep-ph/0511115] [INSPIRE].
P. Meade and M. Reece, Top partners at the LHC: spin and mass measurement, Phys. Rev. D 74 (2006) 015010 [hep-ph/0601124] [INSPIRE].
A. Alves, O. Eboli and T. Plehn, It’s a gluino, Phys. Rev. D 74 (2006) 095010 [hep-ph/0605067] [INSPIRE].
C. Athanasiou, C.G. Lester, J.M. Smillie and B.R. Webber, Distinguishing spins in decay chains at the large hadron collider, JHEP 08 (2006) 055 [hep-ph/0605286] [INSPIRE].
L.-T. Wang and I. Yavin, Spin measurements in cascade decays at the LHC, JHEP 04 (2007) 032 [hep-ph/0605296] [INSPIRE].
J.M. Smillie, Spin correlations in decay chains involving W bosons, Eur. Phys. J. C 51 (2007) 933 [hep-ph/0609296] [INSPIRE].
C. Kilic, L.-T. Wang and I. Yavin, On the existence of angular correlations in decays with heavy matter partners, JHEP 05 (2007) 052 [hep-ph/0703085] [INSPIRE].
A. Alves and O. Eboli, Unravelling the sbottom spin at the CERN LHC, Phys. Rev. D 75 (2007) 115013 [arXiv:0704.0254] [INSPIRE].
C. Csáki, J. Heinonen and M. Perelstein, Testing gluino spin with three-body decays, JHEP 10 (2007) 107 [arXiv:0707.0014] [INSPIRE].
M.R. Buckley, H. Murayama, W. Klemm and V. Rentala, Discriminating spin through quantum interference, Phys. Rev. D 78 (2008) 014028 [arXiv:0711.0364] [INSPIRE].
L.-T. Wang and I. Yavin, A review of spin determination at the LHC, Int. J. Mod. Phys. A 23 (2008) 4647 [arXiv:0802.2726] [INSPIRE].
M.R. Buckley, B. Heinemann, W. Klemm and H. Murayama, Quantum interference effects among helicities at LEP-II and Tevatron, Phys. Rev. D 77 (2008) 113017 [arXiv:0804.0476] [INSPIRE].
M. Burns, K. Kong, K.T. Matchev and M. Park, A general method for model-independent measurements of particle spins, couplings and mixing angles in cascade decays with missing energy at hadron colliders, JHEP 10 (2008) 081 [arXiv:0808.2472] [INSPIRE].
W.S. Cho, K. Choi, Y.G. Kim and C.B. Park, M T2 -assisted on-shell reconstruction of missing momenta and its application to spin measurement at the LHC, Phys. Rev. D 79 (2009) 031701 [arXiv:0810.4853] [INSPIRE].
O. Gedalia, S.J. Lee and G. Perez, Spin determination via third generation cascade decays, Phys. Rev. D 80 (2009) 035012 [arXiv:0901.4438] [INSPIRE].
F. Boudjema and R.K. Singh, A model independent spin analysis of fundamental particles using azimuthal asymmetries, JHEP 07 (2009) 028 [arXiv:0903.4705] [INSPIRE].
W. Ehrenfeld, A. Freitas, A. Landwehr and D. Wyler, Distinguishing spins in decay chains with photons at the large hadron collider, JHEP 07 (2009) 056 [arXiv:0904.1293] [INSPIRE].
L. Edelhauser, W. Porod and R.K. Singh, Spin discrimination in three-body decays, JHEP 08 (2010) 053 [arXiv:1005.3720] [INSPIRE].
D. Horton, Reconstructing events with missing transverse momentum at the LHC and its application to spin measurement, arXiv:1006.0148 [INSPIRE].
H.-C. Cheng, Z. Han, I.-W. Kim and L.-T. Wang, Missing momentum reconstruction and spin measurements at hadron colliders, JHEP 11 (2010) 122 [arXiv:1008.0405] [INSPIRE].
M.R. Buckley and M.J. Ramsey-Musolf, Diagnosing spin at the LHC via vector boson fusion, JHEP 09 (2011) 094 [arXiv:1008.5151] [INSPIRE].
C.-Y. Chen and A. Freitas, General analysis of signals with two leptons and missing energy at the large hadron collider, JHEP 02 (2011) 002 [arXiv:1011.5276] [INSPIRE].
M.M. Nojiri and J. Shu, Two jets and missing E T signature to determine the spins of the new particles, JHEP 06 (2011) 047 [arXiv:1101.2701] [INSPIRE].
G. Moortgat-Pick, K. Rolbiecki and J. Tattersall, Early spin determination at the LHC?, Phys. Lett. B 699 (2011) 158 [arXiv:1102.0293] [INSPIRE].
L. Edelhauser, W. Porod and R.K. Singh, Effects of anomalous couplings on spin determination in cascade decays, arXiv:1109.3369 [INSPIRE].
T. Melia, Spin before mass at the LHC, JHEP 01 (2012) 143 [arXiv:1110.6185] [INSPIRE].
C.-Y. Chen and A. Freitas, General analysis of decay chains with three-body decays involving missing energy, JHEP 01 (2012) 124 [arXiv:1110.6192] [INSPIRE].
M. Burns, K. Kong, K.T. Matchev and M. Park, Using subsystem M T2 for complete mass determinations in decay chains with missing energy at hadron colliders, JHEP 03 (2009) 143 [arXiv:0810.5576] [INSPIRE].
T. Han, I.-W. Kim and J. Song, Kinematic cusps: determining the missing particle mass at colliders, Phys. Lett. B 693 (2010) 575 [arXiv:0906.5009] [INSPIRE].
J. Alwall, A. Freitas and O. Mattelaer, Measuring sparticles with the matrix element, AIP Conf. Proc. 1200 (2010) 442 [arXiv:0910.2522] [INSPIRE].
J. Alwall, A. Freitas and O. Mattelaer, The matrix element method and QCD radiation, Phys. Rev. D 83 (2011) 074010 [arXiv:1010.2263] [INSPIRE].
B. Gripaios, Transverse observables and mass determination at hadron colliders, JHEP 02 (2008) 053 [arXiv:0709.2740] [INSPIRE].
A.J. Barr, B. Gripaios and C.G. Lester, Weighing WIMPs with kinks at colliders: invisible particle mass measurements from endpoints, JHEP 02 (2008) 014 [arXiv:0711.4008] [INSPIRE].
A.J. Barr, B. Gripaios and C.G. Lester, Transverse masses and kinematic constraints: from the boundary to the crease, JHEP 11 (2009) 096 [arXiv:0908.3779] [INSPIRE].
K.T. Matchev, F. Moortgat, L. Pape and M. Park, Precision sparticle spectroscopy in the inclusive same-sign dilepton channel at LHC, Phys. Rev. D 82 (2010) 077701 [arXiv:0909.4300] [INSPIRE].
K.T. Matchev and M. Park, A general method for determining the masses of semi-invisibly decaying particles at hadron colliders, Phys. Rev. Lett. 107 (2011) 061801 [arXiv:0910.1584] [INSPIRE].
P. Konar, K. Kong, K.T. Matchev and M. Park, Superpartner mass measurement technique using 1D orthogonal decompositions of the Cambridge transverse mass variable M T2, Phys. Rev. Lett. 105 (2010) 051802 [arXiv:0910.3679] [INSPIRE].
P. Konar, K. Kong, K.T. Matchev and M. Park, Dark matter particle spectroscopy at the LHC: generalizing M T2 to asymmetric event topologies, JHEP 04 (2010) 086 [arXiv:0911.4126] [INSPIRE].
T. Cohen, E. Kuflik and K.M. Zurek, Extracting the dark matter mass from single stage cascade decays at the LHC, JHEP 11 (2010) 008 [arXiv:1003.2204] [INSPIRE].
W.S. Cho, W. Klemm and M.M. Nojiri, Mass measurement in boosted decay systems at hadron colliders, Phys. Rev. D 84 (2011) 035018 [arXiv:1008.0391] [INSPIRE].
C.B. Park, Reconstructing the heavy resonance at hadron colliders, Phys. Rev. D 84 (2011) 096001 [arXiv:1106.6087] [INSPIRE].
H.-C. Cheng and J. Gu, Measuring invisible particle masses using a single short decay chain, JHEP 10 (2011) 094 [arXiv:1109.3471] [INSPIRE].
S. Chang, K.Y. Lee and J. Song, The second Kaluza-Klein neutral Higgs bosons in the minimal universal extra dimension model, Phys. Lett. B 707 (2012) 144 [arXiv:1101.0670] [INSPIRE].
M. Baumgart, T. Hartman, C. Kilic and L.-T. Wang, Discovery and measurement of sleptons, binos and winos with a Z′, JHEP 11 (2007) 084 [hep-ph/0608172] [INSPIRE].
O. Eboli, C.S. Fong, J. Gonzalez-Fraile and M. Gonzalez-Garcia, Determination of the spin of new resonances in electroweak gauge boson pair production at the LHC, Phys. Rev. D 83 (2011) 095014 [arXiv:1102.3429] [INSPIRE].
G. Burdman, B.A. Dobrescu and E. Ponton, Resonances from two universal extra dimensions, Phys. Rev. D 74 (2006) 075008 [hep-ph/0601186] [INSPIRE].
B.A. Dobrescu, K. Kong and R. Mahbubani, Leptons and photons at the LHC: cascades through spinless adjoints, JHEP 07 (2007) 006 [hep-ph/0703231] [INSPIRE].
H.-C. Cheng, K.T. Matchev and M. Schmaltz, Bosonic supersymmetry? getting fooled at the CERN LHC, Phys. Rev. D 66 (2002) 056006 [hep-ph/0205314] [INSPIRE].
CMS collaboration, G. Bayatian et al., CMS technical design report, volume II: physics performance, J. Phys. G 34 (2007) 995 [INSPIRE].
D.R. Tovey, On measuring the masses of pair-produced semi-invisibly decaying particles at hadron colliders, JHEP 04 (2008) 034 [arXiv:0802.2879] [INSPIRE].
D. Tovey, Measuring the SUSY mass scale at the LHC, Phys. Lett. B 498 (2001) 1 [hep-ph/0006276] [INSPIRE].
P. Konar, K. Kong and K.T. Matchev, \(\sqrt{{{{\widehat{s}}_{\min }}}}\): a global inclusive variable for determining the mass scale of new physics in events with missing energy at hadron colliders, JHEP 03 (2009) 085 [arXiv:0812.1042] [INSPIRE].
P. Konar, K. Kong, K.T. Matchev and M. Park, RECO level \( \sqrt {{{{s}_{{\min }}}}} \) and subsystem \( \sqrt {{{{s}_{{\min }}}}} \): improved global inclusive variables for measuring the new physics mass scale in /ET events at hadron colliders, JHEP 06 (2011) 041 [arXiv:1006.0653] [INSPIRE].
C. Lester and D. Summers, Measuring masses of semiinvisibly decaying particles pair produced at hadron colliders, Phys. Lett. B 463 (1999) 99 [hep-ph/9906349] [INSPIRE].
W.S. Cho, K. Choi, Y.G. Kim and C.B. Park, Measuring superparticle masses at hadron collider using the transverse mass kink, JHEP 02 (2008) 035 [arXiv:0711.4526] [INSPIRE].
W.S. Cho, J.E. Kim and J.-H. Kim, Amplification of endpoint structure for new particle mass measurement at the LHC, Phys. Rev. D 81 (2010) 095010 [arXiv:0912.2354] [INSPIRE].
M.E. Cabrera, J.A. Casas and J.A. Casas, Understanding and improving the effective mass for LHC searches, arXiv:1207.0435 [INSPIRE].
S. Kawabata, Y. Shimizu, Y. Sumino and H. Yokoya, Boost-invariant leptonic observables and reconstruction of parent particle mass, Phys. Lett. B 710 (2012) 658 [arXiv:1107.4460] [INSPIRE].
C. Rogan, Kinematical variables towards new dynamics at the LHC, arXiv:1006.2727 [INSPIRE].
J. Alwall, P. Demin, S. de Visscher, R. Frederix, M. Herquet, et al., MadGraph/MadEvent v4: the new web generation, JHEP 09 (2007) 028 [arXiv:0706.2334] [INSPIRE].
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Edelhäuser, L., Matchev, K.T. & Park, M. Spin effects in the antler event topology at hadron colliders. J. High Energ. Phys. 2012, 6 (2012). https://doi.org/10.1007/JHEP11(2012)006
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DOI: https://doi.org/10.1007/JHEP11(2012)006