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http://hdl.handle.net/10261/49
2016-04-30T15:08:03ZNext-to-leading order corrections to the gluon-induced forward jet vertex from the high energy effective action
http://hdl.handle.net/10261/125951
Title: Next-to-leading order corrections to the gluon-induced forward jet vertex from the high energy effective action
Authors: Chachamis, G.; Hentschinski, M.; Madrigal Martínez, José Daniel; Sabio Vera, Agustín
Abstract: We determine both real and virtual next-to-leading order corrections to the gluon-induced forward jet vertex from the high energy effective action proposed by Lipatov. For these calculations we employ the same regularization and subtraction formalism developed in our previous work on the quark-initiated vertex. We find agreement with previous results in the literature.2015-11-26T08:22:58ZBootstrap and momentum transfer dependence in small x evolution equations
http://hdl.handle.net/10261/125582
Title: Bootstrap and momentum transfer dependence in small x evolution equations
Authors: Chachamis, G.; Sabio Vera, Agustín; Salas, C.
Abstract: Using Monte Carlo integration techniques, we investigate running coupling effects compatible with the high energy bootstrap condition to all orders in the strong coupling in evolution equations valid at small values of Bjorken x in deep inelastic scattering. A model for the running of the coupling with analytic behavior in the infrared region and compatible with power corrections to jet observables is used. As a difference to the fixed coupling case, where the momentum transfer acts as an effective strong cutoff of the diffusion to infrared scales, in our running coupling study the dependence on the momentum transfer is much milder.2015-11-24T09:04:12ZGluon Regge trajectory at two loops from Lipatov's high energy effective action
http://hdl.handle.net/10261/125347
Title: Gluon Regge trajectory at two loops from Lipatov's high energy effective action
Authors: Chachamis, G.; Hentschinski, M.; Madrigal Martínez, José Daniel; Sabio Vera, Agustín
Abstract: We present the derivation of the two-loop gluon Regge trajectory using Lipatov's high energy effective action and a direct evaluation of Feynman diagrams. Using a gauge invariant regularization of high energy divergences by deforming the light-cone vectors of the effective action, we determine the two-loop self-energy of the reggeized gluon, after computing the master integrals involved using the Mellin-Barnes representations technique. The self-energy is further matched to QCD through a recently proposed subtraction prescription. The Regge trajectory of the gluon is then defined through renormalization of the reggeized gluon propagator with respect to high energy divergences. Our result is in agreement with previous computations in the literature, providing a non-trivial test of the effective action and the proposed subtraction and renormalization framework.2015-11-19T11:28:41ZThe health of SUSY after the Higgs discovery and the XENON100 data
http://hdl.handle.net/10261/125046
Title: The health of SUSY after the Higgs discovery and the XENON100 data
Authors: Cabrera, María Eugenia; Casas, Alberto; Ruiz de Austri, Roberto
Abstract: We analyze the implications for the status and prospects of supersymmetry of the Higgs discovery and the last XENON data. We focus mainly, but not only, on the CMSSM and NUHM models. Using a Bayesian approach we determine the distribution of probability in the parameter space of these scenarios. This shows that, most probably, they are now beyond the LHC reach. This negative chances increase further (at more than 95% c.l.) if one includes dark matter constraints in the analysis, in particular the last XENON100 data. However, the models would be probed completely by XENON1T. The mass of the LSP neutralino gets essentially fixed around 1TeV. We do not incorporate ad hoc measures of the fine-tuning to penalize unnatural possibilities: such penalization arises automatically from the careful Bayesian analysis itself, and allows to scan the whole parameter space. In this way, we can explain and resolve the apparent discrepancies between the previous results in the literature. Although SUSY has become hard to detect at LHC, this does not necessarily mean that is very fine-tuned. We use Bayesian techniques to show the experimental Higgs mass is at similar to 2 sigma off the CMSSM or NUHM expectation. This is substantial but not dramatic. Although the CMSSM or the NUHM are unlikely to show up at the LHC, they are still interesting and plausible models after the Higgs observation; and, if they are true, the chances of discovering them in future dark matter experiments are quite high.2015-11-16T08:06:00Z