208 research outputs found
Beyond the standard model: working group report
No full textThis report summarises the work done in the 'Beyond the Standard Model' working group of the Sixth Workshop on High Energy Physics Phenomenology (WHEPP-6) held at the Institute of Mathematical Sciences, Chennai, Jan 3-15, 2000. The participants in this working group were: R Adhikari, B Ananthanarayan, K P S Balaji, Gour Bhattacharya, Gautam Bhattacharyya, Chao-Hsi Chang (Zhang). D Choudhury, Amitava Datta, Anindya Datta, Asesh K Datta, A Dighe, N Gaur, D Ghosh, A Goyal, K Kar, S F King, Anirban Kundu, U Mahanta, R N Mohapatra, B Mukhopadhyaya, S Pakvasa, P N Pandita, M K Parida, P Poulose, G Raffelt, G Rajasekaran, S Rakshit, Asim K Ray, A Raychaudhuri, S Raychaudhuri, D P Roy, P Roy, S Roy, K Sridhar and S Vempati
Is the b quark mixed with a vectorlike quark?
No full textWe examine the possibility of an exotic vectorlike charge (-1/3) quark h mixing with the d-type quarks. The currently accepted Cabibbo-Kobayashi-Maskawa matrix elements, though consistent with unitarity, allow substantial mixing of such an exotic quark with the b quark. Concentrating on h-b mixing, we find several distinctive signatures-in top-quark production and decay, Z→ bb̅ , and flavor-violating rare Z decays-which may be experimentally testable in the near future
B<SUP>0</SUP>-B̅<SUP>0</SUP> mixing in a supersymmetry-inspired two higgs doublet model
No full textA supersymmetry-motivated two Higgs doublet model with equal vacuum expectation values for the two neutral Higgs and with a physical charged Higgs mass of 80-100 GeV is carefully examined in the context of its implications for B0-B̅0 mixing. Even with this conservative choice of Higgs parameters, the lower bound on the top quark mass coming from the ARGUS data is found to be considerably relaxed. An upper bound is also set, using results from CLEO and Mark II
Singlet-Higgs-boson signals at electron-positron colliders
No full textThe possibility of production of singlet Higgs particles coupling to exotic fermions at the CERN e+e− Collider LEP or the SLAC Linear Collider through the loop-induced decay Z0→h0γ is discussed and decay signatures for the singlet Higgs boson are suggested. It appears that singlet Higgs bosons may be detectable with 107 Z0's, if the unknown masses and couplings are in the right range
Low-mass right-handed gauge bosons, manifest left-right symmetry, and the K<SUB>L</SUB>-K<SUB>s</SUB> mass difference
No full textWe calculate the KL-KS mass difference in left-right-symmetric models with four quarks. It is found that a low right-handed mass scale requires strong deviations from manifest left-right symmetry
Rare decay H<SUP>+</SUP>→W<SUP>+</SUP>γin the minimal supersymmetric standard model
No full textThe amplitude for the one-loop-induced decay H+→W+γ is calculated in the 't Hooft-Feynman gauge in the minimal supersymmetric standard model concentrating on the scalar sector only. It is shown that Feynman graphs with gauge bosons, physical and unphysical scalars, and Faddeev-Popov ghosts in the loops undergo large cancellations to contribute negligibly to the final amplitude. The dominant contribution comes from graphs with internal t and b quarks. A numerical evaluation shows that if the charged Higgs boson is lighter than the t quark, then the branching ratio for this process can be as large as ~7×10−5. For a wide range of parameters, this could remain well within the range of detect- ability at the CERN LHC and SSC
Does a low mass right-handed vector boson imply a departure from manifest left-right symmetry?
No full textWe examine the K0-K̅0 complex for constraints on the left-right symmetric model of the electroweak interactions. A light right-handed vector boson is found to require a strong departure from manifest left-right symmetry. The effect on charmed particle decays and other nonleptonic processes are discussed
Detection of charged Higgs bosons through the rare decay H<SUP>+</SUP>→W<SUP>+</SUP>γ
No full textThe process H+→W+γ is evaluated exactly in the 'Hooft-Feynman gauge in a two-Higgs doublet model with scalar masses and couplings of charged Higgs particles lighter than the top quark
Application of the N-quantum approximation method to bound-state problems.I
No full textThe N-quantum approximation (NQA) is examined in the light of its application to the bound state of two scalar particles with scalar exchange. Bound-state wave functions are obtained as expansion coefficients in a truncated Haag expansion. An integral equation satisfied by the wave function is derived from the equations of motion for the Heisenberg fields and the NQA expansions. In the nonrelativistic limit the equation is shown to properly reduce to the Schrödinger equation. The equation is simplified by two different methods and then solved numerically. The results are compared with other calculations
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