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Title: Collider signals of top quark flavor violation from a warped extra dimension

Abstract

We study top quark flavor violation in the framework of a warped extra dimension with the Standard Model (SM) fields propagating in the bulk. Such a scenario provides solutions to both the Planck-weak hierarchy problem and the flavor puzzle of the SM without inducing a flavor problem. We find that, generically, tcZ couplings receive a huge enhancement, in particular, the right-handed ones can be O(1%). This results in BR(t{yields}cZ) at or above the sensitivity of the Large Hadron Collider (LHC). At the International Linear Collider (ILC), single top production, via e{sup +}e{sup -}{yields}tc, can be a striking signal for this scenario. In particular, it represents a physics topic of critical importance that can be explored even with a relatively low energy option, close to the tc threshold. At both the LHC and the ILC, angular distributions can probe the above prediction of dominance of right-handed couplings.

Authors:
 [1];  [2];  [3];  [4]
  1. Department of Physics, Syracuse University, Syracuse, New York 13244 (United States)
  2. Theoretical Physics Group, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States)
  3. (United States)
  4. Brookhaven National Laboratory, Upton, New York 11973 (United States)
Publication Date:
OSTI Identifier:
20933251
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. D, Particles Fields; Journal Volume: 75; Journal Issue: 1; Other Information: DOI: 10.1103/PhysRevD.75.015002; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; ANGULAR DISTRIBUTION; ANNIHILATION; CERN LHC; ELECTRON-POSITRON INTERACTIONS; ELECTRONS; FLAVOR MODEL; LINEAR COLLIDERS; POSITRONS; STANDARD MODEL; T QUARKS

Citation Formats

Agashe, Kaustubh, Perez, Gilad, C.N. Yang Institute for Theoretical Physics, Nicolls Road, Stony Brook University, Stony Brook, NY 11794-3840, and Soni, Amarjit. Collider signals of top quark flavor violation from a warped extra dimension. United States: N. p., 2007. Web. doi:10.1103/PHYSREVD.75.015002.
Agashe, Kaustubh, Perez, Gilad, C.N. Yang Institute for Theoretical Physics, Nicolls Road, Stony Brook University, Stony Brook, NY 11794-3840, & Soni, Amarjit. Collider signals of top quark flavor violation from a warped extra dimension. United States. doi:10.1103/PHYSREVD.75.015002.
Agashe, Kaustubh, Perez, Gilad, C.N. Yang Institute for Theoretical Physics, Nicolls Road, Stony Brook University, Stony Brook, NY 11794-3840, and Soni, Amarjit. Mon . "Collider signals of top quark flavor violation from a warped extra dimension". United States. doi:10.1103/PHYSREVD.75.015002.
@article{osti_20933251,
title = {Collider signals of top quark flavor violation from a warped extra dimension},
author = {Agashe, Kaustubh and Perez, Gilad and C.N. Yang Institute for Theoretical Physics, Nicolls Road, Stony Brook University, Stony Brook, NY 11794-3840 and Soni, Amarjit},
abstractNote = {We study top quark flavor violation in the framework of a warped extra dimension with the Standard Model (SM) fields propagating in the bulk. Such a scenario provides solutions to both the Planck-weak hierarchy problem and the flavor puzzle of the SM without inducing a flavor problem. We find that, generically, tcZ couplings receive a huge enhancement, in particular, the right-handed ones can be O(1%). This results in BR(t{yields}cZ) at or above the sensitivity of the Large Hadron Collider (LHC). At the International Linear Collider (ILC), single top production, via e{sup +}e{sup -}{yields}tc, can be a striking signal for this scenario. In particular, it represents a physics topic of critical importance that can be explored even with a relatively low energy option, close to the tc threshold. At both the LHC and the ILC, angular distributions can probe the above prediction of dominance of right-handed couplings.},
doi = {10.1103/PHYSREVD.75.015002},
journal = {Physical Review. D, Particles Fields},
number = 1,
volume = 75,
place = {United States},
year = {Mon Jan 01 00:00:00 EST 2007},
month = {Mon Jan 01 00:00:00 EST 2007}
}
  • We study top quark flavor violation in the framework of a warped extra dimension with the Standard Model (SM) fields propagating in the bulk. Such a scenario provides solutions to both the Planck-weak hierarchy problem and the flavor puzzle of the SM without inducing a flavor problem. We find that, generically, tcZ couplings receive a huge enhancement, in particular the right handed ones can be {Omicron}(1%). This results in BR (t {yields} cZ) at or above the sensitivity of the Large Hadron Collider (LHC). At the International Linear Collider (ILC), single top production, via e{sup +}e{sup -} {yields} t{bar c},more » can be a striking signal for this scenario. In particular, it represents a physics topic of critical importance that can be explored even with a relatively low energy option, close to the tc threshold. At both the LHC and the ILC, angular distributions can probe the above prediction of dominance of right-handed couplings.« less
  • In models of maximal flavor violation (MxFV) suggested in [S. Bar-Shalom and A. Rajaraman, Phys. Rev. D 77, 095011 (2008).] there is at least one new scalar {phi}{sub FV} which couples to the quarks via {phi}{sub FV}q{sub i}q{sub j}{proportional_to}{xi}{sub ij} where {xi}{sub i3},{xi}{sub 3i}{approx}V{sub tb} for i=1, 2 and {xi}{sub 33}{approx}V{sub td} and V is the CKM matrix. In this article, we explore the potential phenomenological implications of MxFV for collider experiments. We study MxFV signals of same-sign leptons from same-sign top-quark pair production at the Tevatron and at the LHC. We show that the current Tevatron data set hasmore » strong sensitivity to this signature, for which there are no current limits. For example, if m{sub {phi}{sub FV}}{approx}200 GeV and the MxFV coupling {xi} has a natural value of {approx}1, we expect {approx}12 MxFV events to survive a selection requiring a pair of same-sign leptons, a tagged b-jet and missing transverse energy, over a background of approximately 4-5 events.« less
  • We study the same-sign top pair production mediated by the first Kaluza-Klein (KK) excitation of the gluon in the Randall-Sundrum model with flavor violation at the LHC, in which the nonuniversal couplings between fermions and KK gauge bosons will lead to observable tree-level flavor changing neutral current effects. We find that the same-sign top quarks produced in our case have property of high energy and high transverse momentum, and lead to an observable signal in the same-sign dilepton channel even when the mass of the KK gluon reach up to 3 TeV. We further investigate the potential of the LHCmore » to probe the flavor violating parameters and find that the LHC can probe their values down to 0.06.« less
  • In view of the fact that the n=1 Kaluza-Klein (KK) modes in a model with a universal extra dimension could mimic supersymmetry signatures at the LHC, it is necessary to look for the n=2 KK modes, which have no analogues in supersymmetry. We discuss the possibility of searching for heavy n=2 vector boson resonances--especially the g{sub 2}--through their decays to a highly boosted top quark-antiquark pair using recently developed top-jet tagging techniques in the hadronic channel. It is shown that tt signals from the n=2 gluon resonance are as efficient a discovery mode at the LHC as dilepton channels frommore » the {gamma}{sub 2} and Z{sub 2} resonances.« less
  • We study predictions for B-physics in a class of models, recently introduced, with a non-supersymmetric warped extra dimension. In these models few ({approx} 3) TeV Kaluza-Klein masses are consistent with electroweak data due to bulk custodial symmetry. Furthermore, there is an analog of GIM mechanism which is violated by the heavy top quark (just as in SM) leading to striking signals at B-factories: (1) New Physics (NP) contributions to {Delta}F = 2 transitions are comparable to SM. This implies that, within this NP framework, the success of the SM unitarity triangle fit is a ''coincidence''. Thus, clean extractions of unitaritymore » angles via e.g. B {yields} {pi}{pi}, {rho}{pi}, {rho}{rho}, DK are likely to be affected, in addition to O(1) deviation from SM prediction in Bs mixing. (2) O(1) deviation from SM predictions for B {yields} X{sub s}{ell}{sup +}{ell}{sup -} in rate as well as in forward-backward and direct CP asymmetry. (3) Large mixing-induced CP asymmetry in radiative B decays, wherein the SM unambiguously predicts very small asymmetries. Also, with KK masses 3 TeV or less, and with anarchic Yukawa masses, contributions to electric dipole moments of the neutron are roughly 20 times larger than the current experimental bound so that this framework has a ''CP problem''.« less