arXiv subjects

Veronique Page

Publications and source records attributed to Veronique Page.

7 recordsLinked to original sources

arXiv2007

Non-thermal right-handed sneutrino dark matter and the Omega_DM/Omega_b problem

We argue that the superpartner of the Dirac right-handed neutrino is a prime candidate for dark matter created from a 'mattergenesis' mechanism. We show that due to the smallness of the Yukawa couplings, a right-handed sneutrino density created in the early Universe would not be erased by annihilations, which remain out of thermal equilibrium. It would also not be drowned by a later, additional production of right-handed sneutrinos, as the relic density of the non-thermal right-handed sneutrinos is found to be generally negligible compared to the observed dark matter density. Mild constraints on sneutrino masses and trilinear SUSY-breaking couplings are obtained. Possible mattergenesis scenarios are also mentioned

hep-ph↗

arXiv2006

(Pseudo)-Dirac neutrinos and leptogenesis

We discuss how Dirac neutrinos can naturally be generated in supersymmetry and how they allow for an Affleck-Dine leptogenesis scenario, in which a left-right asymmetry is generated in the sneutrino sector, the left part of which is transferred to a baryon asymmetry via sphaleron transitions. No exotic fields need to be added to the MSSM other than the right-handed neutrino.

hep-ph↗

arXiv2006

Affleck-Dine (Pseudo)-Dirac Neutrinogenesis

We consider the Affleck-Dine mechanism for leptogenesis in the minimal MSSM with Dirac or Pseudo-Dirac neutrinos. The rolling of scalars along D-flat directions generates a left-right asymmetry in the sneutrino sector, only the left part of which is transferred to a baryon asymmetry via sphaleron transitions. In the pure Dirac case the baryon asymmetry of the Universe is thus mirrored by an equal and opposite asymmetry in the leptons. The mechanism is also found to work when the neutrinos are pseudo-Dirac. No additional field needs to be added to the MSSM other than the right-handed neutrino.

hep-ph↗

arXiv2005

Methods for Measuring New-Physics Parameters in B Decays

Recently, it was argued that new-physics (NP) effects in B decays can be approximately parametrized in terms of a few quantities. As a result, CP violation in the $B$ system allows one not only to detect the presence of new physics (NP), but also to measure its parameters. This will allow a partial identification of the NP, before its production at high-energy colliders. In this paper, we examine three methods for measuring NP parameters. The first uses a technique involving both $\btos$ and $\btod$ penguin B decays. Depending on which pair of decays is used, the theoretical error is in the range 5--15%. The second involves a comparison of $B\to πK$ and $B\toππ$ decays. Although the theoretical error is large ($\gsim 25%$), the method can be performed now, with presently-available data. The third is via a time-dependent angular analysis of $\bvv$ decays. In this case, there is no theoretical error, but the technique is experimentally challenging, and the method applies only to those NP models whose weak phase is universal to all NP operators. A reliable identification of the NP will involve the measurement of the NP parameters in many different ways, and with as many B decay modes as possible, so that it will be important to use all of these methods.

hep-ph↗

arXiv2004

New Physics Signals through CP Violation in B -> rho,pi

We describe here a method for detecting physics beyond the standard model via CP violation in B->rho,pi decays. Using a Dalitz-plot analysis to obtain alpha, along with an analytical extraction of the various tree (T) and penguin (P) amplitudes, we obtain a criterion for the absence of new physics (NP). This criterion involves the comparison of the measured |P/T| ratio with its value as predicted by QCD factorization. We show that the detection of NP via this method has a good efficiency when compared with the corresponding technique using B->pi,pi decays.

hep-ph↗

arXiv2004

CP Violation in B -> rho pi: New Physics Signals

A Dalitz-plot analysis of Bd(t) -> rho pi -> pi+ pi- pi0 decays allows one to obtain the CP-violating phase α. In addition, one can extract the various tree (T) and penguin (P) amplitudes contributing to these decays. By comparing the measured value of |P/T| with the theoretical prediction, one can detect the presence of physics beyond the standard model.

hep-ph↗

arXiv2003

Obtaining the Full Unitarity Triangle from B -> pi K Decays

We present a method of obtaining the entire unitarity triangle from measurements of B -> pi K decay rates alone. Electroweak penguin amplitudes are included, and are related to tree operators. Discrete ambiguities are removed by comparing solutions with independent experimental data. The theoretical uncertainty in this method is rather small, in the range 5--10%.

hep-ph↗