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Please use this identifier to cite or link to this item: http://hdl.handle.net/10481/30581

Title: Effective four-fermion operators in top physics: A roadmap
Authors: Aguilar-Saavedra, Juan Antonio
Issue Date: 2011
Abstract: We write down a minimal basis for dimension-six gauge-invariant four-fermion operators, with some operator replacements with respect to previous ones which make it simpler for calculations. Using this basis we classify all four-fermion operator contributions involving one or two top quarks. Taking into account the different fermion chiralities, possible colour contractions and independent flavour combinations, a total number of 572 gauge-invariant operators are involved. We apply this to calculate all three-body top decay widths t -> d_k u_i dbar_j, t -> d_k e_i+ nu_j, t -> u_k u_i ubar_j, t -> u_k e_j+ e_i-, t -> u_k nu_j nu_i (with i,j,k generation indices) mediated by dimension-six four-fermion operators, including the interference with the Standard Model amplitudes when present. All single top production cross sections in pp, p pbar and e+ e- collisions are calculated as well, namely u_i d_k -> d_j t, dbar_j d_k -> ubar_i t, u_i dbar_j -> dbar_k t, u_i u_k -> u_j t, u_i ubar_j -> ubar_k t, e+ e- -> ubar_k t and the charge conjugate processes. We also compute all top pair production cross sections, ubar_i u_j -> t tbar, dbar_i d_j -> t tbar, u_i u_j -> t t and e+ e- -> t tbar. Our results are completely general, without assuming any particular relation among effective operator coefficients.
Sponsorship: This work has been partially supported by a MICINN Ramón y Cajal contract and by projects FPA2006-05294 (MICINN), FQM 101 and FQM 437 (Junta de Andalucía), CERN/FP/83588/2008 (FCT), and by the European Community's Marie-Curie Research Training Network under contract MRTN-CT-2006-035505 “Tools and Precision Calculations for Physics Discoveries at Colliders”.
Publisher: Elsevier
Keywords: Fermion
Operators
Physics
URI: http://hdl.handle.net/10481/30581
ISSN: 0550-3213
Rights : Creative Commons Attribution-NonCommercial-NoDerivs 3.0 License
Citation: Aguilar-Saavedra, J.A. Effective four-fermion operators in top physics: A roadmap. Nuclear Physics B, 843(3): 638-672 (2011). [http://hdl.handle.net/10481/30581]
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