Ref HAL: in2p3-00182623_v1
Ref Arxiv: 0707.2070
DOI: 10.1103/PhysRevD.77.063524
Ref. & Cit.: NASA ADS
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62 citations
Résumé:

Charged massive particles (CHAMPs), when present during the Big Bang nucleosynthesis (BBN) era, may significantly alter the synthesis of light elements when compared to a standard BBN scenario. This is due to the formation of bound states with nuclei. This paper presents a detailed numerical and analytical analysis of such CHAMP BBN. All reactions important for predicting light-element yields are calculated within the Born approximation. Three priorly neglected effects are treated in detail:(a) photodestruction of bound states due to electromagnetic cascades induced by the CHAMP decay, (b) late-time efficient destruction/production of H2, Li6, and Li7 due to reactions on charge Z=1 nuclei bound to CHAMPs, and (c) CHAMP exchange between nuclei. Each of these effects may induce orders-of-magnitude changes in the final abundance yields. The study focusses on the impact of CHAMPs on a possible simultaneous solution of the Li6 and Li7 problems. It is shown that a priorly suggested simultaneous solution of the Li6 and Li7 problems for a relic decaying at tau_x = 1000 sec is only very weakly dependent on the relic being neutral or charged, unless its hadronic branching ratio is Bh << 10^-4 very small. By use of a Monte-Carlo analysis it is shown that within CHAMP BBN the existence of further parameter space for a simultaneous solution of the Li6 and Li7 problem for long decay times tau_x > 10^6 sec seems possible but fairly unlikely.

Commentaires: 15 pages (revtex), 14 figures, large changes in analysis and conclusions

Ref HAL: in2p3-00175941_v1
Ref Arxiv: 0709.1789
DOI: 10.1103/PhysRevD.77.013003
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11 citations
Résumé:

We present a complete 1-loop study of the electroweak corrections to the process $ug\to dW^+$ in MSSM and SM. The occurrence of a number of remarkable properties in the behavior of the helicity amplitudes at high energies is stressed, and the crucial role of the virtual SUSY contributions in establishing them, is emphasized. The approach to asymptopia of these amplitudes is discussed, comparing the effects of the logarithmic and constant contributions to the mass suppressed ones, which are relevant at lower energies. Applying crossing to $ug\to d W^+$, we obtain all subprocesses needed for the 1-loop electroweak corrections to $W^\pm$-production at LHC. The SUSY model dependence in such a production is then studied, and illustrations are given for the transverse $W^{\pm}$ momentum distribution.

Ref HAL: in2p3-00175932_v1
Ref Arxiv: 0707.0628
DOI: 10.1088/1475-7516/2007/11/009
Ref. & Cit.: NASA ADS
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47 citations
Résumé:

We explore the parameter space of the Constrained Next-to-Minimal Supersymmetric Standard Model with GUT scale boundary conditions (CNMSSM) and find regions where the relic density of the lightest neutralino is compatible with the WMAP measurement. We emphasize differences with the MSSM: cases where annihilation of the LSP occurs via a Higgs resonance at low values of tan\beta and cases where the LSP has a large singlino component. The particle spectrum as well as theoretical and collider constraints are calculated with NMSSMTools. All neutralino annihilation and coannihilation processes are then computed with micrOMEGAs, taking into account higher order corrections to the Higgs sector.

Commentaires: 17 pages.

Ref HAL: in2p3-00149106_v1
Ref Arxiv: 0705.3101
DOI: 10.1140/epjc/s10052-007-0452-y
Ref. & Cit.: NASA ADS
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10 citations
Résumé:

We compute, in the MSSM framework, the sum of the one-loop electroweak and of the total QED radiation effects for the process $pp \to t W+X$, initiated by the parton process $bg\to tW$. Combining these terms with the existing NLO calculations of SM and SUSY QCD corrections, we analyze the overall one-loop supersymmetric effects on the partial rates of the process, obtained by integrating the differential cross section up to a final variable invariant mass. We conclude that, for some choices of the SUSY parameters and for relatively small final invariant masses, they could become relevant under realistic experimental conditions at LHC.

Commentaires: 20 pp.

Ref HAL: hal-00296026_v1
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Résumé:

Contribution to the 5th Workshop on Flavor in the Era of the LHC (26-29 March 2007, Geneva, Switzerland ; Flavor and Top Physics, WG1.

Ref HAL: hal-00300690_v1
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Résumé:

Flavour and Top Physics, WG1.

Ref Arxiv: hep-ph/0602198
Ref. & Cit.: NASA ADS
Résumé:

The work contained herein constitutes a report of the "Beyond the StandardModel'' working group for the Workshop "Physics at TeV Colliders", Les Houches,France, 2-20 May, 2005. We present reviews of current topics as well asoriginal research carried out for the workshop. Supersymmetric andnon-supersymmetric models are studied, as well as computational tools designedin order to facilitate their phenomenology.

Commentaires: 269 pages, 165 figures. Web page of the workshop (with links to the talks) http://lappweb.in2p3.fr/conferences/LesHouches/Houches2005/