Search for heavy neutral and charged leptons in e+e− annihilation at LEP

Achard, P.; Адриани, О.; Aguilar-Benı́tez, M.; Alcaraz, J.; Alemanni, G.; Allaby, J.; Aloisio, A.; Alviggi, M. G.; Anderhub, H.; Andreev, V.; Anselmo, F.; Arefiev, A.; Azemoon, T.; Aziz, T.; Baarmand, M. M.; Bagnaia, P.; Bajo, A.; Baksay, G.; Baksay, L.; Baldew, S.V.; Banerjee, S.; Barczyk, A.; Barillère, R.; Bartalini, P.; Basile, M.; Batalova, N.; Battiston, R.; Bay, A.; Becattini, F.; Becker, U.; Behner, F.; Bellucci, L.; Berbeco, R.; Berdugo, J.; Berges, P.; Bertucci, B.; Betev, B. L.; Biasini, M.; Biland, A.; Blaising, J. J.; Blyth, S.; Bobbink, G. J.; Böhm, A.; Boldizsár, L.; Borgia, B.; Bourilkov, D.; Bourquin, M.; Braccini, S.; Branson, J. G.; Brochu, F. M.; Buijs, A.; Bürger, J.; Burger, W. J.; Cai, X.; Capell, M.; Romeo, Giovanni; Carlino, G.; Cartacci, A. M.; Casaus, J.; Cavallari, F.; Cavallo, N.; Cecchi, C.; Cerrada, M.; Chamizo, M.; Chang, Y. H.; Chemarin, M.; Chen, A.; Chen, G.; Chen, G.M.; Chen, H.F.; Chen, H.S.; Chiefari, G.; Cifarelli, L.; Cindolo, F.; Clare, I.; Clare, R.; Coignet, G.; Colino, N.; Costantini, S.; Cruz, B. De La; Cucciarelli, S.; Dai, T.; Dalen, J. A. van; Asmundis, R. de; Déglon, P.; Debreczeni, J.; Degré, A.; Deiters, K.; Volpe, D. della; Delmeire, E.; Denes, P.; DeNotaristefani, F.; Salvo, A. De; Diemoz, M.; Dierckxsens, M.; Dierendonck, D. van; Dionisi, C.; Dittmar, M.; Doria, A.; Dova, M. T.; Duchesneau, D.; Duinker, P.; Echenard, B.; Eline, A.; Mamouni, H. El; Engler, A.; Eppling, F. J.; Ewers, A.; Extermann, P.; Falagán, M. A.; Falciano, S.; Favara, A.; Fay, J.; Fedin, O. L.; Felcini, M.; Ferguson, T.; Fesefeldt, H.; Fiandrini, E.; Field, J. H.; Filthaut, F.; Fisher, P. H.; Fisher, W.; Fisk, I.; Forconì, G.; Freudenreich, K.; Furetta, C.; Galaktionov, Yu.; Ganguli, S.N.; Garcı́a-Abia, P.; Gataullin, M.; Gentile, S.; Giagu, S.; Gong, Z. F.; Grenier, G.; Grimm, O.; Gruenewald, M. W.; Guida, M.; Gulik, R. van; Gupta, V. K.; Gurtu, A.; Gutay, L.; Haas, D.; Hatzifotiadou, D.; Hebbeker, T.; Hervé, A.; Hirschfelder, J.; Hofer, H.; Holzner, G.; Hou, S.; Hu, Y.; Jin, B. N.; Jones, L. W.; Jong, P. de; Josa-Mutuberrı́a, I.; Käfer, D.; Kaur, M.; Kienzle‐Focacci, M. N.; Kim, J.K.; Kirkby, J.; Kittel, W.; Klimentov, A.; König, A. C.; Kopál, M.; Koutsenko, V.; Kräber, M.; Kraemer, R.W.; Krenz, W.; Krüger, A.; Kunin, A.; Guevara, P. Ladrón de; Laktineh, I. B.; Landi, G.; Lebeau, M.; Lebedev, A.; Lebrun, P.; Lecomte, P.; Lecoq, P.; Coultre, P. Le; Lee, H.J.; Goff, J. M. Le; Leiste, R.; Levtchenko, P.; Li, C.; Likhoded, S.; Lin, C. H.; Lin, W.; Linde, F.L.; Lista, L.; Liu, Z.A.; Lohmann, W.; Longo, E.; Lu, Y. S.; Lübelsmeyer, K.; Luci, C.; Luckey, D.; Luminari, L.; Lustermann, W.; Ma, W.G.; Malgeri, L.; Малинин, А.; Mañá, C.; Mangeol, D.; Mans, J.; Martín, J. P.; Marzano, F.; Mazumdar, K.; McNeil, R. R.; Mele, S.; Merola, L.; Meschini, M.; Metzger, W. J.; Mihul, A.; Milcent, H.; Mirabelli, G.; Mnich, J.; Mohanty, G. B.; Muanza, G. S.; Muijs, A. J.M.; Musicar, B.; Musy, M.; Nagy, S.; Napolitano, M.; Nessi‐Tedaldi, F.; Newman, H. B.; Nießen, T.; Nisati, A.; Nowak, H.; Ofierzynski, R. A.; Organtini, G.; Palomares, C.; Pandoulas, D.; Paolucci, P.; Paramatti, R.; Passaleva, G.; Patricelli, S.; Paul, T.; Pauluzzi, M.; Paus, C.; Pauß, F.; Pedace, M.; Pensotti, S.; Perret-Gallix, D.; Petersen, B. A.; Piccolo, D.; Pierella, F.; Piroué, P.; Pistolesi, E.; Plyaskin, V.; Pohl, M.; Pojidaev, V.; Postema, H.; Pothier, J.; Prokofiev, D.; Quartieri, J.; Rahal-Callot, G.; Rahaman, M. A.; Raics, P.; Raja, N.; Ramelli, R.; Rancoita, P.G.; Ranieri, R.; Raspereza, A.; Razis, P. A.; Ren, D.; Rescigno, M.; Reucroft, S.; Riemann, S.; Riles, K.; Roe, B.P.; Romero, L.; Rosca, A.; Rosier‐Lees, S.; Roth, Stefan; Rosenbleck, C.; Roux, B.; Rubio, J. A.; Ruggiero, G.; Rykaczewski, H.; Sakharov, A.; Saremi, S.; Sarkar, S.; Salicio, J.; Sánchez, E.; Sanders, M. P.; Schäfer, C.; Schegelsky, V. A.; Schmidt-Kaerst, S.; Schmitz, D.; Schopper, H.; Schotanus, D. J.; Schwering, G.; Sciacca, C.; Servoli, L.; Shevchenko, S.; Shivarov, N.; Shoutko, V.; Shumilov, E.; Shvorob, A.; Siedenburg, T.; Son, D. C.; Спиллантини, П.; Steuer, M.; Stickland, D.; Stoyanov, B.; Straessner, A.; Sudhakar, K.; Sultanov, G.; Sun, L. Z.; Sushkov, S.; Suter, H.; Swain, J. D.; Szillási, Z.; Tang, X. W.; Tarján, P.; Tauscher, L.; Taylor, L.; Tellili, B.; Teyssier, D.; Timmermans, C.; Ting, Samuel C.C.; Ting, S. M.; Tonwar, S. C.; Töth, J.; Tully, C.; Tung, K. L.; Uchida, Y.; Ulbricht, J.; Valente, E.; Veszprémi, V.; Vesztergombi, G.; Vetlitsky, I.; Vicinanza, D.; Viertel, G.; Villa, S.; Vivargent, M.; Vlachos, S.; Vodopianov, I.; Vogel, H.; Vogt, H.; Vorobiev, I.; Vorobyov, A. A.; Wadhwa, M.; Walle, R. T. Van de; Wallraff, W.; Wang, M.; Wang, X.L.; Wang, Z.M.; Weber, M.; Wienemann, P.; Wilkens, H. G.; Wu, S. X.; Wynhoff, S.; Xia, L.; Xu, Z.; Yamamoto, J.; Yang, B. Z.; Yang, C. G.; Yang, H. J.; Yang, Min; Yeh, S. C.; Zalite, A.; Zalite, Yu.; Zhang, Z.P.; Zhao, J.; Zhu, G. Y.; Zhu, R. Y.; Zhuang, H.L.; Zichichi, A.; Zilizi, G.; Zimmermann, B.; Zöller, Margot

doi:10.1016/s0370-2693(01)01005-x

Cited by 165 publications

(129 citation statements)

References 47 publications

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“…To obtain the limit of |U e4 U * µ4 | < 4·10 −4 the authors of Ref. [11] used the search limit for the heavy neutrino mass, m ν 4 = 90.3 GeV [42]. Within our analysis the limit on this product is significantly looser, |U e4 U * µ4 | < 1.16·10 −3 (2σ level), since we conservatively take m ν 4 > m Z /2.…”

Section: Discussionmentioning

confidence: 99%

“…Using the LEP search limit, m E > 100 GeV at 90 % CL [42], one finds sin θ 34 < 0.13. Since sin θ 34 ≈ |U τ 4 | (in the Botella-Chau parametrisation [31]) our findings are in agreement with such a scenario if m E is at least of order 240 GeV.…”

Section: Discussionmentioning

confidence: 99%

“…Therefore one can not escape the constraints from radiative lepton decays. Since the mass limits from LEP2 on a fourth generation neutrino are only valid for unstable neutrinos [42] these limits depend implicitely on the mass of the heavy charged lepton and on the size of the PMNS matrix elements. To extract numerical results that are independent from these assumptions we choose for the heavy neutrino mass the robust constraint m ν 4 > m Z /2 resulting from the LEP1 measurements of the Z-resonance [17].…”

Section: Introductionmentioning

confidence: 99%

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Simultaneous extraction of the Fermi constant and PMNS matrix elements in the presence of a fourth generation

Lacker

Menzel

2010

J. High Energ. Phys.

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Simultaneous Extraction of the Fermi constant and PMNS matrix elements in the presence of a fourth generationSeveral recent studies performed on constraints of a fourth generation of quarks and leptons suffer from the ad-hoc assumption that 3 × 3 unitarity holds for the first three generations in the neutrino sector. Only under this assumption one is able to determine the Fermi constant G F from the muon lifetime measurement with the claimed precision of G F = 1.16637(1) × 10 −5 GeV −2 . We study how well G F can be extracted within the framework of four generations from leptonic and radiative µ and τ decays, as well as from K ℓ3 decays and leptonic decays of charged pions, and we discuss the role of lepton universality tests in this context. We emphasize that constraints on a fourth generation from quark and lepton flavour observables and from electroweak precision observables can only be obtained in a consistent way if these three sectors are considered simultaneously. In the combined fit to leptonic and radiative µ and τ decays, K ℓ3 decays and leptonic decays of charged pions we find a p-value of 2.6 % for the fourth generation matrix element |U e4 | = 0 of the neutrino mixing matrix.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Simultaneous extraction of the Fermi constant and PMNS matrix elements in the presence of a fourth generation

Lacker

Menzel

2010

J. High Energ. Phys.

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“…A similar sensitivity could be expected for κ + 2 . Concerning VL fermions, the searches performed at LEPII impose a limit of m χ 1 > 100 GeV [58]. At the LHC, the larger exclusion for VL fermion is expected for large mass splittings, 100% branching ratios to electron or muons, and higher fermions SU(2) L representations.…”

Section: Numerical Results and Discussionmentioning

confidence: 99%

The inert Zee model

Longas

Portillo

Restrepo

et al. 2016

J. High Energ. Phys.

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We study a realization of the topology of the Zee model for the generation of neutrino masses at one-loop with a minimal set of vector-like fermions. After imposing an exact Z 2 symmetry to avoid tree-level Higgs-mediated flavor changing neutral currents, one dark matter candidate is obtained from the subjacent inert doublet model, but with the presence of new co-annihilating particles. We show that the model is consistent with the constraints coming from lepton flavor violation processes, oblique parameters, dark matter and neutrino oscillation data.

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“…Direct searches at LHC have also produced bounds on the masses of vector-like quarks [42][43][44][45][46]. The only dedicated study that provides direct bounds on the masses of vector-like leptons we consider is provided by the LEP L3 collaboration [47]. The effective couplings of these states to the SM fields are constrained through experimental data on processes such as µ-e conversion in nuclei and lepton number violating decays.…”

Section: Introductionmentioning

confidence: 99%

Light vectorlike fermions in a minimalSU(5)setup

2014

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The Standard Model fermion sector is enlarged by either one light singlet vector-like downtype quark or one light vector-like lepton doublet, which might be accommodated within a fivedimensional representation of SU (5). At low energies the inclusion of these states affects precisely measured observables in flavor physics, as well as electroweak precision measurements. These experimental results strongly constrain couplings of vector-like states to the Standard Model particles. Having these bounds, we investigate the impact of vector-like fermions on the mass matrices for down-type quarks and charged leptons in an SU (5) setting. We find that unitary transformations relating an arbitrary flavor basis to the mass eigenstate basis depend only on three free parameters. Then we discuss the parameter space constrained by low-energy data assuming vector-like quark and vector-like lepton masses to be 800 GeV and 400 GeV, respectively. We demonstrate that these two scenarios generate unique patterns for relevant proton decay widths. A further improvement of experimental bounds on proton decay modes would thus differentiate the allowed parameter space. We finally present two full-fledged SU (5) models that allow for gauge coupling unification with light vector-like fermions under consideration and discuss their viability. * Electronic address:ilja.dorsner@ijs.si † Electronic address:svjetlana.fajfer@ijs.si ‡ Electronic address:ivana.mustac@ijs.si

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Search for heavy neutral and charged leptons in e+e− annihilation at LEP

Cited by 165 publications

References 47 publications

Simultaneous extraction of the Fermi constant and PMNS matrix elements in the presence of a fourth generation

Simultaneous extraction of the Fermi constant and PMNS matrix elements in the presence of a fourth generation

The inert Zee model

Light vectorlike fermions in a minimalSU(5)setup

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