Like-sign dimuon charge asymmetry in Randall-Sundurm model

We confirm that in order to account for the recent D\O\ result of large like-sign dimuon charge asymmetry, a considerable large new physics effect in $\Gamma_{12}^s$ is required in addition to a large CP violating phase in $B_s -\bar{B}_s$ mixing. In the Randall-Sundrum model of warped geometry, where the fermion fields reside in the bulk, new sources of flavor and CP violation are obtained. We analyze the like-sign dimuon asymmetry in this class of model, as an example of the desired new physics. We show that the wrong charge asymmetry, $a_{sl}^s$, which is related to the dimuon asymmetry, is significantly altered compared to the Standard Model value. However, experimental limits from $\Delta M_s$, $\Delta\Gamma_s$ as well as $K$ mixing and electroweak corrections constrain it to be greater than a $\sigma$ away from its experimental average value. This model cannot fully account for the D\O\ anomaly due to its inability to generate sufficient new contribution to the width difference $\Gamma^s_{12}$, even though the model can generate large contribution to the mass difference $M^s_{12}$.Comment: 20 pages, 9 figures, discussions and references added, accepted for publication in Physical Review

On supersymmetric contributions to the CP asymmetry of the B -> phi K_S

We analyse the CP asymmetry of the B -> phi K_S process in general supersymmetric models. In the framework of the mass insertion approximation, we derive model independent limits for the mixing CP asymmetry. We show that chromomagnetic type of operator may play an important role in accounting for the deviation of the mixing CP asymmetry between B -> phi K_S and B -> J/psi K_S processes observed by Belle and BaBar experiments. A possible correlation between the direct and mixing CP asymmetry is also discussed. Finally, we apply our result in minimal supergravity model and supersymmetric models with non-universal soft terms.Comment: 19 pages, 3 figure

Gauging U(1) symmetries and the number of right-handed neutrinos

In this letter we consider that assuming: a) that the only left-handed neutral fermions are the active neutrinos, b) that $B-L$ is a gauge symmetry, and c) that the $L$ assignment is restricted to the integer numbers, the anomaly cancellation imply that at least three right-handed neutrinos must be added to the minimal representation content of the electroweak standard model. However, two types of models arise: i) the usual one where each of the three identical right-handed neutrinos has total lepton number L=1; ii) and the other one in which two of them carry L=4 while the third one carries $L=-5$.Comment: Published version in PLB forma

The B→KπB \to K\pi Puzzle and Supersymmetric Models

In the light of new experimental results on $B \to K\pi$ decays, we study the decay processes $B \to K \pi$ in the framework of both R-parity conserving (SUGRA) and R-parity violating supersymmetric models. We find that any possible deviations from the Standard Model indicated by the current data for the branching ratios and the direct CP asymmetries of $B \to K\pi$ can be explained in both R-parity conserving SUGRA and R-parity violating SUSY models. However, there is a difference between the predictions of both models to the time-dependent CP asymmetry observable $S_{K_{_S} \pi^0}$ whose current experimental results include large uncertainties. We demonstrate that this difference can be useful for testing both models with more accurate data for $S_{K_{S} \pi^0}$ and $A_{CP}^{+-}$ in the near future.Comment: 14 pages, 3 figure

Implication of scalar-pseudoscalar mixing on ϵ′/ϵ\epsilon'/\epsilon in SUSY models

We study the effects of scalar-pseudoscalar mixing induced from quantum loop on $\epsilon'/\epsilon$ in SUSY models with $\tan\beta\sim m_{t}/m_{b}$. We find that even the non-universal soft ${\cal A}^{d}$ term and Yukawa matrix, $Y^{d}$, are hermitian, the predicted value of $|\epsilon'/\epsilon|$ can be consistent with the measured results of NA48 and KTeV. And also the EDMs are compatible with experimental bounds.Comment: 11 pages, 1 figure, one typo corrected, to appear in Phys. Lett.

A solution to B --> pi pi puzzle and B --> K K

The large ratio of color-suppressed tree amplitude to color-allowed one in $B \to \pi \pi$ decays is difficult to understand within the Standard Model, which is known as the "$B \to \pi\pi$ puzzle". The two tree diagrams contain the up- and charm-quark component of penguin amplitude, $P_{uc}$, which cannot be separated by measuring $B \to \pi \pi$ decays alone. We show that the measurements of the branching ratio and direct CP asymmetry of $B^+ \to K^+ \bar{K^0}$ decay enable one to disentangle the $P_{uc}$ with two-fold ambiguity. One of the two degenerate solutions of the $P_{uc}$ can solve the $B \to \pi \pi$ puzzle by giving $|C/T|\sim 0.3$ which is consistent with the expectation in the Standard Model. We also show that the two solutions can be discriminated by the measurement of the indirect CP-asymmetry of B^0 \to K^0 \ol{K^0}. We point out that if the $B \to \pi \pi$ puzzle is solved in this way, the corresponding puzzle in $B \to \pi K$ decays should have a different origin.Comment: 12 pages, 2 figures, minor changes, references adde

First Lattice Calculation of the Electromagnetic Operator Amplitude <pi0|Q+|K0>

We present the first lattice calculation of the matrix element of the electromagnetic operator , where Q+ = (Q_d e/16 pi^2)* (\bar s_L sigma{mu,nu} F{mu,nu} d_R + \bar s_R sigma{mu,nu} F{mu,nu} d_L). This matrix element plays an important role, since it contributes to enhance the CP violating part of the K_L -> pi0 e+ e- amplitude in supersymmetric extensions of the Standard Model.Comment: 12 pages, 3 figure

New Source of CP violation in B physics ?

In this talk we discuss how the down type left-right squark mixing in Supersymmetry can induce a new source of CP violation in the time dependent asymmtries in B --> phi K process. We use QCD improved factorization process to calculate the hadronic matrix element for the process and find the allowed parameter space for $\rho$ and $\phi$, the magnitude and phase of the down type LR(RL) squark mixing parameter $\delta^{bs}_{LR(RL)}$. In the same allowed regin we calculate the expected CP asymmtries in the $B \to \phi K^{*}$ process.Comment: 16 pages, Latex, 2 postscript figures, invited talk presented by N.G. Deshpande at the 9th Adriatic meeting, Dubrovnik, Croatia, 4-14 September, 2003. With updated reference

Fully supersymmetric CP violations in the kaon system

We show that, on the contrary to the usual claims, fully supersymmetric CP violations in the kaon system are possible through the gluino mediated flavor changing interactions. Both $\epsilon_K$ and ${\rm Re} (\epsilon' / \epsilon_K)$ can be accommodated for relatively large $\tan\beta$ without any fine tunings or contradictions to the FCNC and EDM constraints.Comment: Contribution to the Proceedings of ICHEP2000, Osaka, 200

Parameters in a Class of Leptophilic Dark Matter Models from PAMELA, ATIC and FERMI

In this work we study a class of leptophilic dark matter models, where the dark matter interacts with the standard model particles via the $U(1)_{L_i-L_j}$ gauge boson, to explain the $e^{\pm}$ excess in cosmic rays observed by ATIC and PAMELA experiments, and more recently by Fermi experiment. There are three types of $U(1)_{L_i-L_j}$ models: a) $U(1)_{L_e - L_\mu}$, b) $U(1)_{L_e - L_{\tau}}$, and c) $U(1)_ {L_e-L_\tau}$. Although ATIC or Fermi data is consistent with PAMELA data separately, ATIC and Fermi data do not agree with each other. We therefore aim to identify which of the three models can explain which data set better. We find that models a) and b) can give correct dark matter relic density and explain the ATIC and PAMELA data simultaneously recur to the Breit-Wigner enhancement. Whereas model c) with a larger $Z^\prime$ mass can explain Fermi and PAMELA data simultaneously. In all cases the model parameters are restricted to narrow regions. Future improved data will decide which set of data are correct and also help to decide the correct dark matter model.Comment: Latex 15 pages with 5 figures. Modified to include discussions of recent Fermi data on the leptophilic models studied in this paper. Title also modifie