The latest data from the ACME Collaboration have put a stringent constraint on the electric dipole moment d e of the electron. Nevertheless, the standard model (SM) prediction for d e is many orders of magnitude below the new result, making this observable a powerful probe for physics beyond the SM. We carry out a model-independent study of d e in the SM with right handed neutrinos and its extension with the neutrino seesaw mechanism under the framework of minimal flavor violation. We find that d e crucially depends on whether neutrinos are Dirac or Majorana particles. In the Majorana case, d e can reach its experimental bound, and it constrains the scale of minimal flavor violation to be above a few hundred GeV or more. We also explore extra CP -violating sources in the Yukawa couplings of the right-handed neutrinos. Such new sources can have important effects on d e .

Abstract:We study the electric dipole moments (EDMs) of fermions in the standard model supplemented with right-handed neutrinos and its extension including the neutrino seesaw mechanism under the framework of minimal flavor violation (MFV). In the quark sector, we find that the current experimental bound on the neutron EDM does not yield a significant restriction on the scale of MFV. In addition, we consider how MFV may affect the contribution of the strong theta-term to the neutron EDM. For the leptons, the existing EDM data also do not lead to strict limits if neutrinos are Dirac particles. On the other hand, if neutrinos are Majorana in nature, we find that the constraints become substantially stronger. Moreover, the results of the latest search for the electron EDM by the ACME Collaboration are sensitive to the MFV scale of order a few hundred GeV or higher. We also look at constraints from CP -violating electron-nucleon interactions that have been probed in atomic and molecular EDM searches.

Using fluorescence microscopy and single-particle tracking, we have directly observed the dynamics of λ-DNA trapped inside poly­(acrylamide-co-acrylate) hydrogels under an externally applied electric field. Congruent with the recent discovery of the nondiffusive topologically frustrated dynamical state (TFDS) that emerges at intermediate confinements between the traditional entropic barrier and reptation regimes, we observe the immobility of λ-DNA in the absence of an electric field. The electrophoretic mobility of the molecule is triggered upon application of an electric field with strength above a threshold value E c. The existence of the threshold value to elicit mobility is attributed to a large entropic barrier, arising from many entropic traps acting simultaneously on a single molecule. Using the measured E c which depends on the extent of confinement, we have determined the net entropic barrier of up to 130 k B T, which is responsible for the long-lived metastable TFDS. The net entropic barrier from multiple entropic traps is nonmonotonic with the extent of confinement and tends to vanish at the boundaries of the TFDS with the single-entropic barrier regime at lower confinements and the reptation regime at higher confinements. We present an estimate of the mesh size of the hydrogel that switches off the nondiffusive TFDS and releases chin diffusion in the heavily entangled state.

Recently the ATLAS and CMS experiments at the LHC have found a Higgs like boson h with a mass around 125 GeV from several decay modes. The decay mode h → γγ is one of the most important modes in studying whether h is actually the standard model (SM) Higgs boson. Current data indicate that h → γγ has a branching ratio larger than the SM prediction for h being identified as the SM Higgs boson. To decide whether the h discovered at the LHC is the SM Higgs boson, more data are needed. We study how γγ collider can help to provide some of the most important information about the Higgs boson properties. We show that a γγ collider can easily verify whether the enhanced h → γγ observed at the LHC hold. Different models can be tested by studying Higgs boson decay to γZ. Studying angular distribution of the γγ through on-shell production of h and its subsequent decays into a γγ pair can decide whether the Higgs like boson h at the LHC is a spin-0 or a spin-2 boson.

The LHCb collaboration has recently measured the first direct CP violation in B 0 s decays with a rate asymmetry A CP (B 0 s → K − π + ) given by 0.27 ± 0.04(stat) ± 0.01(syst). At the same time they also made the most precise measurement forin the standard model with SU (3) flavor symmetry. We discuss possible modifications due to SU (3) breaking effects to this relation. There are several other similar relations in B decays. Using current available data we study whether relevant relations hold in B 0 and B 0 s to P P and P V decays. Here P and V indicate pesudoscalar and vector mesons in the flavor octet representations.