منابع مشابه
Model independent constraints on leptoquarks from rare processes
We present model independent constraints on the masses and couplings to fermions of B and L conserving leptoquarks. Such vector or scalar particles could have masses below 100 GeV and be produced at HERA; we list the generation dependent bounds that can be calculated from rare lepton and meson decays, meson-anti-meson mixing and various electroweak tests.
متن کاملConstraints from Precision Electroweak Data on Leptoquarks and Bileptons
Explicit expressions are derived for the oblique parameters S and T in certain extensions of the standard model. In particular, we consider leptoquarks and bileptons, and find phenomenological constraints on their allowed masses. Leptoquarks suggested by the neutral and charged current anomalies at HERA can give improved agreement with both S and T . If bileptons are the only new states, the si...
متن کاملBounds on vector leptoquarks.
We derive bounds on vector leptoquarks coupling to the first generation, using data from low energy experiments as well as from high energy accelerators. Similarly to the case of scalar leptoquarks, we find that the strongest indirect bounds arise from atomic parity violation and universality in leptonic π decays. These bounds are considerably stronger than the first direct bounds of HERA, rest...
متن کاملNew bounds on leptoquarks.
We derive new bounds on scalar leptoquark couplings from K − K̄, D − D̄ and B − B̄ mixing. Although leptoquarks contribute to these processes only at one loop, their contribution is large, due to the lack of GIM cancelation. Our bounds have two important features: (i) They bound g/M, in contrast to the hitherto known bounds on g/M, and are consequently stronger at high masses. (ii) The bound from ...
متن کاملModel independent constraints on leptoquarks from μ and τ lepton rare processes
We perform a model independent analysis so as to constrain the leptoquark (LQ) models from negative searches for μ → eγ, μ → 3e decays (and analogous processes in the τ sector), and coherent μ−e conversion in nuclei. We considerably improve some constraints obtained by analyses known in the literature, analyses which we show have by far underestimated the LQ contributions to the μ→ 3e. In parti...
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ژورنال
عنوان ژورنال: Physics Letters B
سال: 1986
ISSN: 0370-2693
DOI: 10.1016/0370-2693(86)90771-9