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We determine the neutralino and chargino masses in the MSSM at one-loop. We perform a Feynman diagram calculation in the on-shell renormalization scheme, including quark/squark and lepton/slepton loops. We find generically the corrections…

High Energy Physics - Phenomenology · Physics 2009-08-12 Damien Pierce , Aris Papadopoulos

Radiative one-loop corrections to fermion pair production in $e^+e^-$ annihilation are calculated in the Minimal Supersymmetric Standard Model (MSSM). The size of the non-standard corrections is discussed for the process e^+e^- to mu^+mu^-…

High Energy Physics - Phenomenology · Physics 2009-10-31 W. Hollik , C. Schappacher

Neutralino as the lightest supersymmetric particle (LSP) is a candidate for supersymmetric dark matter. It is known that coannihilation effects could be important in neutralino relic density calculation. Here we present some results on…

High Energy Physics - Phenomenology · Physics 2009-11-07 Yudi Santoso

The complete 1-loop computation of the processes $(\tchi^0_i \tchi^0_j \leftrightarrow\gamma\gamma, ~ gg)$, for any pair of the four MSSM neutralinos, has been performed for an arbitrary c.m energy. As a first application suitable for Dark…

High Energy Physics - Phenomenology · Physics 2011-07-19 G. J. Gounaris , J. Layssac , P. I. Porfyriadis , F. M. Renard

Coannihilation processes provide an important additional mechanism for reducing the density of stable relics in the Universe. In the case of the stable lightest neutralino of the MSSM, and in particular the Constrained MSSM (CMSSM), the…

High Energy Physics - Phenomenology · Physics 2009-11-07 Takeshi Nihei , Leszek Roszkowski , Roberto Ruiz de Austri

We have developed a general formalism to compute Sommerfeld enhancement (SE) factors for a multi-state system of fermions, in all possible spin configurations and with generic long-range interactions. We show how to include such SE effects…

High Energy Physics - Phenomenology · Physics 2011-03-30 Andrzej Hryczuk , Roberto Iengo , Piero Ullio

We present a precise calculation of the lightest neutral Higgs boson production associated with top quark pair at a linear collider. The full one-loop electroweak ${\cal O}(\alpha_{ew})$ contributions to the process $e^+e^- \to t\bar t h^0$…

High Energy Physics - Phenomenology · Physics 2007-05-23 Liu Jing-Jing , Ma Wen-Gan , Han Liang , Zhang Ren-You , Jiang Yi , Wu Peng

We present a code to compute the relic density of dark matter in the Next-to-Minimal Supersymmetric Standard Model (NMSSM). Dominant corrections to the Higgs masses are calculated with NMHDECAY as well as theoretical and collider…

High Energy Physics - Phenomenology · Physics 2009-11-11 G. Belanger , F. Boudjema , C. Hugonie , A. Pukhov , A. Semenov

We evaluate the relic density of the lightest neutralino, the lightest supersymmetric particle, in the Minimal Supersymmetric extension of the Standard Model (MSSM). For the first time, we include all coannihilation processes between…

High Energy Physics - Phenomenology · Physics 2008-11-26 J. Edsjo , P. Gondolo

We consider the effects of neutralino-stau coannihilations on the cosmological relic density of the lightest supersymmetric particle (LSP) $\chi$ in the minimal supersymmetric extension of the Standard Model (MSSM), particularly in the…

High Energy Physics - Phenomenology · Physics 2008-11-26 John Ellis , Toby Falk , Keith A. Olive

In the Minimal Supersymmetric Standard Model (MSSM) we incorporate the Higgs-boson propagator corrections, evaluated up to two-loop order, into the prediction of $\Gamma$(h -> ff) and BR(h -> ff) for f = b, c, $\tau$. The propagator…

High Energy Physics - Phenomenology · Physics 2011-09-13 S. Heinemeyer , W. Hollik , G. Weiglein

We discuss the impact of the two-loop corrections to the Higgs mass in the NMSSM beyond $O(\alpha_S(\alpha_b + \alpha_t))$. For this purpose we use the combination of the public tools SARAH and SPheno to include all contributions stemming…

High Energy Physics - Phenomenology · Physics 2015-03-05 Mark D. Goodsell , Kilian Nickel , Florian Staub

We compute the one-loop supersymmetric QCD quantum effects on the width $\Gamma (t\rightarrow W^{+}\, b)$ of the canonical main decay of the top quark within the framework of the MSSM. The corrections can be of either sign depending on…

High Energy Physics - Phenomenology · Physics 2009-10-28 Andreas DABELSTEIN , Wolfgang HOLLIK , Christoph JUENGER , Ricardo A. JIMENEZ , Joan SOLA

With the latest Planck results the dark matter relic density is determined to an unprecedented precision. In order to reduce current theoretical uncertainties in the dark matter relic density prediction, we have calculated next-to-leading…

High Energy Physics - Phenomenology · Physics 2015-10-22 Julia Harz , Björn Herrmann , Michael Klasen , Karol Kovarik , Patrick Steppeler

We present the full one-loop radiative corrections to pair production of neutralinos in e+e- collisions within the Minimal Supersymmetric Standard Model. Particular attention is paid to the definition of weak and QED corrections. The…

High Energy Physics - Phenomenology · Physics 2010-04-05 W. Oeller , H. Eberl , W. Majerotto

The flux of cosmic ray antiprotons from neutralino annihilations in the galactic halo is computed for a large sample of models in the MSSM (the Minimal Supersymmetric extension of the Standard Model). We also revisit the problem of…

Astrophysics · Physics 2009-10-31 L. Bergstrom , J. Edsjo , P. Ullio

We derive a full set of exact, analytic expressions for the annihilation of the lightest neutralino pairs into all two-body tree-level final states in the framework of minimal supersymmetry. We make no simplifying assumptions about the…

High Energy Physics - Phenomenology · Physics 2014-11-17 Takeshi Nihei , Leszek Roszkowski , Roberto Ruiz de Austri

I discuss recent developments in the study of cosmological limits on the Minimal Supersymmetric Standard Model (MSSM). In particular, I focus on the effect of neutralino-stau coannihilation on the relic abundance of neutralinos, and I give…

High Energy Physics - Phenomenology · Physics 2011-04-15 Toby Falk

We discuss the radiative corrections to charged and neutral current deep-inelastic neutrino--nucleon scattering in the minimal supersymmetric standard model (MSSM). In particular, deviations from the Standard Model prediction for the ratios…

High Energy Physics - Phenomenology · Physics 2007-05-23 O. Brein , B. Koch , W. Hollik

Assuming that the lightest supersymmetric particle (LSP) is the lightest neutralino, we present a detailed exploration of neutralino-stau coannihilation channels, including analytical expressions and numerical results. We also include…

High Energy Physics - Phenomenology · Physics 2009-09-11 J. Ellis , T. Falk , K. A. Olive , M. Srednicki