Search for excited leptons at LEP

Akrawy, M. Z.; Alexander, G.; Allison, J.; Allport, P. P.; Anderson, K. J.; Armitage, John C.; Arnison, G.; Ashton, P.; Azuelos, G.; Baines, J. T.; Ball, A. H.; Banks, J.; Barker, G. J.; Barlow, R. J.; Batley, J. R.; Becker, J.; Behnke, T.; Bell, K. W.; Bella, G.; Bethke, S.; Biebel, O.; Binder, U.; Bloodworth, I. J.; Bock, P.; Breuker, H.; Brown, R. M.; Brun, R.; Buijs, A.; Burckhart, H.; Capiluppi, P.; Carnegie, R. K.; Carter, A.A.; Carter, J.R.; Chang, C. Y.; Charlton, David; Chrin, J.; Cohen, I.; Collins, W. J.; Conboy, J. E.; Couch, M.; Coupland, M.; Cuffiani, M.; Dado, S.; Dallavalle, G. M.; Debu, P.; Deninno, M. M.; Dieckmann, A.; Dittmar, M.; Dixit, M. S.; Duchovni, E.; Duerdoth, I. P.; Dumas, D. J.P.; Mamouni, H. El; Elcombe, P. A.; Estabrooks, P. G.; Etzion, E.; Fabbri, F.; Farthouat, P.; Fischer, H. M.; Fong, D. G.; French, M. T.; Fukunaga, C.; Gaidot, A.; Ganel, O.; Gary, J. W.; Gascon, J.; Geddes, N. I.; Gee, C. N. P.; Geich-Gimbel, Ch.; Gensler, S. W.; Gentit, F. X.; Giacomelli, G.; Gibson, V.; Gibson, W. R.; Gillies, J. D.; Goldberg, J.; Goodrick, M. J.; Gorn, W.; Granite, D.; Gross, E.; Grosse‐Wiesmann, P.; Grunhaus, J.; Hagedorn, H.; Hagemann, J.; Hansroul, M.; Hargrove, C. K.; Hart, J. C.; Hattersley, P. M.; Hauschild, M.; Hawkes, C. M.; Heflin, E.; Hemingway, R. J.; Heuer, R. D.; Hill, J. C.; Hillier, S. J.; Ho, C.; Hobbs, J.; Hobson, P. R.; Hochman, D.; Holl, B.; Homer, R. J.; Hou, S.; Howarth, C. P.; Hughes-Jones, R. E.; Igo‐Kemenes, P.; Ihssen, H.; Imrie, D. C.; Jawahery, A.; Jeffreys, P. W.; Jérémie, H.; Jimack, M.; Jobes, M.; Jones, Roger; Jovanović, P.; Karlen, D.; Kawagoe, K.; Kawamoto, T.; Kellogg, R. G.; Kennedy, B. W.; Kleinwort, C.; Klem, D. E.; Knop, G.; Kobayashi, T.; Kokott, T. P.; Köpke, L.; Kowalewski, R.; Kreutzmann, H.; Krogh, J. von; Kroll, J.; Kuwano, M.; Kyberd, P.; Lafferty, G.; Lamarche, F.; Larson, W. J.; Layter, J. G.; Dû, P. Le; Leblanc, P.; Lee, A.M.; Lellouch, D.; Lennert, P.; Lessard, L.; Levinson, L. J.; Lloyd, S. L.; Loebinger, F. K.; Lorah, J. M.; Lorazo, B.; Losty, M. J.; Ludwig, J.; Lupu, N.; Ma, J.; Macbeth, A. A.; Mannelli, M.; Marcellini, S.; Maringer, G.; Martín, A.; Martín, J. P.; Mäshimo, T.; Mättig, P.; Maur, U.; McMahon, T. J.; McPherson, A. C.; Meijers, F.; Menszner, D.; Merritt, F. S.; Mes, H.; Michelini, A.; Middleton, R. P.; Mikenberg, G.; Miller, D. J.; Milstène, C.; Minowa, M.; Mohr, W.; Montanari, A.; Mori, T.; Moss, M. W.; Murphy, P. G.; Murray, W. J.; Nellen, B.; Nguyen, H. H.; Nozaki, M.; O'Dowd, A. J.P.; O’Neale, S. W.; O'Neill, B. P.; Oakham, F. G.; Odorici, F.; Ogg, M.; Oh, H.; Oreglia, M. J.; Orito, S.; Pansart, J. P.; Patrick, G. N.; Pawley, S. J.; Pfister, P.; Pilcher, J. E.; Pinfold, J. L.; Plane, D. E.; Poli, B.; Pouladdej, A.; Pritchard, T. W.; Quast, G.; Raab, J.; Redmond, M. W.; Rees, D. L.; Regimbald, M.; Riles, K.; Roach, C. M.; Robins, S. A.; Rollnik, A.; Roney, J. M.; Rossberg, S.; Rossi, A. M.; Routenburg, P.; Runge, K.; Runólfsson, Ö.; Sanghera, S.; Sansum, R. A.; Sasaki, M.; Saunders, B. J.; Schaile, A. D.; Schappert, W.; Scharff-Hansen, P.; Schmitt, H. von der; Schreiber, S.; Schwarz, J.; Shapira, A.; Shen, B. C.; Sherwood, P.; Simon, A.; Singh, P.; Siroli, G. P.; Skuja, A.; Smith, A. M.; Smith, T. J.; Snow, G. A.; Spreadbury, E. J.; Springer, R. W.; Sproston, M.; Stephens, K.; Stier, H. E.; Ströhmer, R.; Strom, D.; Takeda, Hiroshi; Takeshita, T.; Tsukamoto, T.; Turner, M.; Tysarczyk-Niemeyer, G.; plas, D. Van den; VanDalen, G. J.; Vasseur, G.; Virtue, C. J.; Wagner, A.; Wahl, C.; Ward, C. P.; Ward, D. R.; Waterhouse, J.; Watkins, P. M.; Watson, A. T.; Watson, N. K.; Weber, M.; Weisz, S.; Wermes, N.; Weymann, M.; Wilson, G. W.; Wilson, J. A.; Wingerter, Isabelle; Winterer, V. H.; Wood, N. C.; Wotton, S. A.; Wuensch, B. J.; Wyatt, T. R.; Yaari, R.; Yang, Y. C.; Yekutieli, G.; Yoshida, Takashi; Zeuner, W. D.; Zorn, G. T.

doi:10.1016/j.physletb.2003.05.004

Cited by 32 publications

(22 citation statements)

References 36 publications

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“…The H1 limits as a function of excited fermion mass are shown in figure 51, where they are compared to limits from LEP (excited electrons: [247,248], excited neutrinos: [249], excited quarks: [250]) and the Tevatron (excited electrons: [251]). Analyses from the LHC by ATLAS and CMS using their √ s = 8 TeV data have recently pushed these limits into a new mass regime, where, under the assumption f = f ′ = 1 and Λ = M f * , excited electrons (quarks) are ruled out by ATLAS at the 95% CL for masses lower than 2.2 TeV [252] (3.5 TeV [253]).…”

Section: H1mentioning

confidence: 99%

Review of searches for rare processes and physics beyond the Standard Model at HERA

South

Turcato

2016

Eur. Phys. J. C

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The electron-proton collisions collected by the H1 and ZEUS experiments at HERA comprise a unique particle physics data set, and a comprehensive range of measurements has been performed to provide new insight into the structure of the proton. The high centre of mass energy at HERA has also allowed rare processes to be studied, including the production of W and Z 0 bosons and events with multiple leptons in the final state. The data have also opened up a new domain to searches for physics beyond the Standard Model including contact interactions, leptoquarks, excited fermions and a number of supersymmetric models. This review presents a summary of such results, where the analyses reported correspond to an integrated luminosity of up to 1 fb −1 , representing the complete data set recorded by the H1 and ZEUS experiments.

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Section: H1mentioning

confidence: 99%

Review of searches for rare processes and physics beyond the Standard Model at HERA

South

Turcato

2016

Eur. Phys. J. C

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“…The scaling parameters f s , f , and f are assumed to be equal to one. Previous searches at LEP [4][5][6][7], HERA [8,9], and the Tevatron [10][11][12][13] have found no evidence for such excited leptons. Searches for qq contact interactions performed by studying the dilepton production at the Tevatron [14,15] and LHC [16] have resulted in lower limits on this search is the Drell-Yan production of + − pairs, accompanied by a photon radiated either by an initial-state parton (ISR) or from one of the final-state leptons (FSR).…”

Section: + (L → R)mentioning

confidence: 99%

“…The scaling parameters f s , f , and f are assumed to be equal to one. Previous searches at LEP [4][5][6][7], HERA [8,9], and the Tevatron [10-13] have found no evidence for such excited leptons. Searches for qq contact interactions performed by studying the dilepton production at the Tevatron [14,15] This Letter presents a search for excited leptons in pp collision data collected in 2010 at a centre-of-mass energy of 7 TeV with the Compact Muon Solenoid (CMS) [17] detector at the Large Hadron Collider (LHC).…”

mentioning

confidence: 99%

Search for Excited Leptons in pp collisions at \sqrt s = 7 TeV

Jain¹

2014

Proceedings of the European Physical Society Conference on High Energy Physics — PoS(EPS-HEP 2013)

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Keywords: CMS PhysicsA search for excited leptons is carried out with the CMS detector at the LHC, using 36 pb −1 of pp collision data recorded atThe search is performed for associated production of a lepton and an oppositely charged excited lepton pp → * , followed by the decay * → γ , resulting in the γ final state, where = e, μ. No excess of events above the standard model expectation is observed. Interpreting the findings in the context of * production through four-fermion contact interactions and subsequent decay via electroweak processes, first upper limits are reported for * production at this collision energy.The exclusion region in the compositeness scale Λ and excited lepton mass M * parameter space is extended beyond previously established limits. For Λ = M * , excited lepton masses are excluded below 1070 GeV/c 2 for e * and 1090 GeV/c 2 for μ * at the 95% confidence level.© 2011 CERN. Published by Elsevier B.V. All rights reserved. IntroductionA fundamental question in the standard model (SM) of particle physics concerns the source of the mass hierarchy of quarks and leptons. A possible explanation for the three generations is a compositeness model in which the known leptons and quarks are bound states of either three fermions or a fermion-boson pair [1]. This substructure, if it exists, implies a large spectrum of excited states. Novel strong interactions would couple the excited fermions to ordinary quarks and leptons. These contact interactions can be described with an effective Lagrangian [2]:where Λ is the compositeness or contact interaction scale, g * 2 represents a coupling constant chosen to be 4π , and j μ is the fermion current:The SM and excited fermions are denoted by f and f * , respectively. The subscripts L (R) refer to left-(right-) handed fermions.The η factors for left-handed currents are conventionally set to one, and those for right-handed currents are set to zero. The excited fermions are assumed to have spin and isospin of 1/2. Gaugemediated transitions between ordinary and excited fermions are ✩ © CERN, for the benefit of the CMS Collaboration.E-mail address: cms-publication-committee-chair@cern.ch.described by an effective Lagrangian [2,3]:where G a μν , W μν , and B μν are the field strength tensors of the gluon, SU(2), and U(1) gauge fields, respectively, and g s , g, and g are the corresponding gauge couplings. The scaling parameters f s , f , and f are assumed to be equal to one. Previous searches at LEP [4][5][6][7], HERA [8,9], and the Tevatron [10-13] have found no evidence for such excited leptons. Searches for qq contact interactions performed by studying the dilepton production at the Tevatron [14,15] This Letter presents a search for excited leptons in pp collision data collected in 2010 at a centre-of-mass energy of 7 TeV with the Compact Muon Solenoid (CMS) [17] detector at the Large Hadron Collider (LHC). The data sample corresponds to an integrated luminosity of 36 pb −1 . The production of an excited lepton * (μ * or e * ) in association with an oppositely c...

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“…GeV [16]. Assuming f = f ′ and f /Λ = 1/m ⋆ , for single production of excited spin-1/2 neutrino in ep collisions taking into account all the decay channels, the H1 Collaboration set the exclusion limit for the mass range of excited neutrino m ⋆ > 213 GeV at 95% C.L.…”

Section: Introductionmentioning

confidence: 99%

Search for Excited Spin-3/2 Neutrinos at LHeC

Ozansoy

Arı

Çetinkaya

2016

Advances in High Energy Physics

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We study the potential of the next ep collider, namely LHeC, with two options √ s = 1.3 TeV √ s = 1.98 TeV, to search for excited spin-1/2 and spin-3/2 neutrinos. We calculate the single production cross section of excited spin-1/2 and spin-3/2 neutrinos according to their effective currents describing their interactions between gauge bosons and SM leptons. We choose the ν ⋆ → eW decay mode of excited neutrinos and W → jj decay mode of W -boson for the analysis. We put some kinematical cuts for the final state detectable particles and plot the invariant mass distributions for signal and the corresponding backgrounds. In order to obtain accessible limits for excited neutrino couplings, we show the f − f ′ and c iV − c iA contour plots for excited spin-1/2 and excited spin-3/2 neutrinos, respectively.

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Search for excited leptons at LEP

Cited by 32 publications

References 36 publications

Review of searches for rare processes and physics beyond the Standard Model at HERA

Review of searches for rare processes and physics beyond the Standard Model at HERA

Search for Excited Leptons in pp collisions at \sqrt s = 7 TeV

Search for Excited Spin-3/2 Neutrinos at LHeC

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