Large CP Research Articles

Implications of large CP violation in B mixing for Supersymmetric Standard Models

Following the anomalous like-sign dimuon charge asymmetry measured by the D0 collaboration at the Tevatron collider we discuss the implications of large CP violation in $B_{d,s}$ mixing for Supersymmetric (SUSY) Standard Models, focussing on those models which allow a family symmetry and unification. For the Minimal Supersymmetric Standard Model (MSSM) we show that it is only possible to account for $B_{s}$ mixing and CP violation at the expense of large squark mixing which would require a new approach to family symmetry models. In order to describe both $B_{s}$ and $B_{d}$ mixing and CP violation we are led to consider SUSY models with Higgs fields transforming as triplets under a family symmetry. We describe a realistic such model based on $\Delta_{27}$ family symmetry in which tree-level exchange of the second Higgs family predicts $B_{s}$ and $B_{d}$ mixing and CP violation in good agreement with a recent global fit, while naturally suppressing flavour and CP violation involving the first and second quark and lepton families.

Annihilation-type charmless radiative decays of B meson in non-universal Z′ model

We study charmless pure annihilation type radiative B decays within the QCD factorization approach. After adding the vertex corrections to the naive factorization approach, we find that the branching ratios of $\bar{B}^0_d\to\phi\gamma$, $\bar{B}^0_s\to\rho^0\gamma$ and $\bar{B}^0_s\to\omega\gamma$ within the standard model are at the order of $\mathcal{O}(10^{-12})$, $\mathcal{O}(10^{-10})$ and $\mathcal{O}(10^{-11})$, respectively. The smallness of these decays in the standard model makes them sensitive probes of flavor physics beyond the standard model. To explore their physics potential, we have estimated the contribution of $Z^\prime$ boson in the decays. Within the allowed parameter space, the branching ratios of these decay modes can be enhanced remarkably in the non-universal $Z^\prime$ model: The branching ratios can reach to $\mathcal{O}(10^{-8})$ for $\bar B_s^0 \to \rho^0(\omega)\gamma$ and $\mathcal{O}(10^{-10})$ for the $\bar B_d^0 \to \phi \gamma$, which are large enough for LHC-b and/or Super B-factories to detect those channels in near future. Moreover, we also predict large CP asymmetries in suitable parameter space. The observation of these modes could in turn help us to constrain the $Z'$ mass within the model.

Flavour physics in the Littlest Higgs Model with T‐parity: effects in the K, Bd/s and D systems

AbstractThe Littlest Higgs Model with T parity (LHT) is an interesting alternative model for New Physics at the TeV scale. Although Flavour Physics was not the reason for creating the LHT model, significant effects (such as large CP violation where not predicted by the SM) can be created without violating existing experimental bounds. We study the B‐, K‐ and especially the D‐sector.

Studying ofBs→K(*)−π+,K(*)−ρ+decays within supersymmetry

Recent results from CDF Collaboration favor a large CP asymmetry in $B_s\rightarrow K^-\pi^+$ decay, while the Standard Model prediction is very small. Moreover, the measurement of its branching ratio is lower than the Standard Model prediction based on the QCD factorization. We compute the gluino-mediated supersymmetry contributions to $B_{s}\to K^{(*)-}\pi^{+}$,$K^{(*)-}\rho^{+}$ decays in the frame of the mass insertion method, and find that for $\frac{m^2_{\tilde{g}}}{m^2_{\tilde{q}}}\leq2$, the theoretical predictions including the LR and RL mass insertion contributions are compatible with the measurements of $B_s\to K^-\pi^+$ decay and $B^0-\bar{B}^0$ mixing within $2\sigma$ ranges. Using the constrained LR and RL mass insertion parameter spaces, we explore the supersymmetry mass insertion effects on the branching ratios, the direct CP asymmetries and the polarization fractions in $B_{s}\to K^{*-}\pi^+, K^{-}\rho^+, K^{*-}\rho^+$ decays. We find the constrained LR and RL insertions can provide sizable contributions to the branching ratios of $B_{s}\to K^{*-}\pi^{+}$,$K^{(*)-}\rho^{+}$ as well as the direct CP asymmetry and the longitudinal polarization of $B_{s}\to K^{*-}\rho^{+}$ decay without conflict with all related data within $2\sigma$ ranges. Near future experiments at Fermi Lab and CERN LHC-b can test our predictions and shrink/reveal the mass insertion parameter spaces.

Decays ofBmeson to two charmed mesons

The factorization theorem in Decays of $B_{(s)}$ mesons to two charmed mesons (both pseudoscalar and vector) can still be proved in the leading order in $m_D/m_B$ and $\Lambda_{\rm{QCD}}/m_D$ expansion. Working in the perturbative QCD approach, we find that the factorizable emission diagrams are dominant. Most of branching ratios we compute agree with the experimental data well, which means that the factorization theorem seems to be reliable in predicting branching ratios for these decays. In the decays of a $B$ meson to two vector charmed mesons, the transverse polarization states contribute $40%-50%$ both in the processes with an external W emission and in the pure annihilation decays. This is in agreement with the present experimental data. We also calculate the CP asymmetry parameters. The results show that the direct CP asymmetries are very small. Thus observation of any large direct CP asymmetry will be a signal for new physics. The mixing induced CP asymmetry in the neutral modes is large. This is also in agreement with the current experimental measurements. They can give a cross check of the $\sin 2\beta$ measurement from other channels.

CP phase of nonuniversal [formula omitted] on [formula omitted] and T-odd observables of [formula omitted

The evidence of a large CP phase has been shown by CDF and DØ collaborations in the time-dependent CP asymmetry (CPA) of Bs→J/Ψϕ decay, where the nonvanished CPA clearly implies the existence of a non-Kobayashi–Maskawa phase in b→s transition. We study the new phases originated by the extra family-dependent U(1)′ model and examine their impact on Tˆ or CP violating observables in B¯q→Vqℓ+ℓ− decays with Vq=K∗(ϕ). Adopting the constraints from the current data of Δms and the branching ratios for B¯s→μ+μ− and B¯q→Vqℓ+ℓ−, we find that ϕsJ/Ψϕ=−(0.26±0.22) and the T-odd observables of above 10% in the decay chain B¯q→Vq(→Kπ[KK])ℓ+ℓ− can be achieved. In addition, we demonstrate that the longitudinal and transverse polarizations of K∗ and the up-down asymmetry of K in the same decay chain are also sensitive to the Z′-mediated effects.

Formula omitted] puzzle and new sources of CP violation in supersymmetry

The difference between the CP asymmetries of the B0→K+π− and B+→K+π0 decays has been recently confirmed with an evidence larger than 5σ's. We discuss it as a possible signal of new physics associated with new (large) CP violation in the electroweak penguin contributions. We propose a supersymmetry breaking scheme where such new sources of CP violation occur in the flavor non-universal trilinear scalar couplings.

Supersymmetry andCPviolation inBs0−B¯s0mixing andBs0→J/ψϕdecay

Supersymmetric contributions to time independent asymmetry in B{sub s}{sup 0}{yields}J/{psi}{phi} process are analyzed in view of recent Tevatron experimental measurements. We show that the experimental limits of the mass difference {delta}M{sub B{sub s}} and the mercury electric dipole moment significantly constrain the supersymmetric (SUSY) contribution to B{sub s}{sup 0}-B{sub s}{sup 0} mixing, so that sin2{beta}{sub s} < or approx. 0.1. We also point out that the one loop SUSY contribution to B{sub s}{sup 0}{yields}J/{psi}{phi} decay can be important and can lead to large indirect CP asymmetries which are different for different polarization states. These new physics effects in the decay amplitude can be consistent with CP measurements in the B{sub d} system.

Origin of the enthalpy features of water in 1.8 nm pores of MCM-41 and the large Cp increase at 210 K

It is shown that exothermic and endothermic features of dH(m)/dt observed on heating rapidly precooled and slowly precooled states of water in 1.8 nm pores of MCM-41 and the unusually large increase in the specific heat in the 210-230 K range [M. Oguni, Y. Kanke, S. Namba, and AIP Conf, Proc. 982, 34 (2008)] are inconsistent with kinetic unfreezing of a disordered solid, or glass softening. The exotherm is attributable to the melt's gradual conversion to distorted icelike structures and the endotherm to the reverse process until their fractional amounts reach a reversible equilibrium on heating. The large increase in C(p,m) with T is attributed to the latent heat, similar to that seen on premelting of fine grain crystals. The available calorimetric data on freezing and melting and the pore-size dependence of the features support this interpretation. The findings also put into question a conclusion from neutron scattering studies that in 1.8 nm pores water undergoes a structural and kinetic transition at approximately 225 K while remaining a liquid.

Measurement of CP violation in stop cascade decays at the LHC

We study the potential observation at the LHC of CP-violating effects in stop production and subsequent cascade decays, $gg\to \tilde{t}_{i}\tilde{t}_{i}$ , $\tilde{t}_{i}\to t\tilde{\chi}^{0}_{j}$ , $\tilde{\chi}^{0}_{j}\to \tilde{\chi}^{0}_{1}\ell^{+}\ell^{-}$ , within the Minimal Supersymmetric Standard Model. We study T-odd asymmetries based on triple products between the different decay products. There may be a large CP asymmetry at the parton level, but there is a significant dilution at the hadronic level after integrating over the parton distribution functions. Consequently, even for scenarios where large CP intrinsic asymmetries are expected, the measurable asymmetry is rather small. High luminosity and precise measurements of masses, branching ratios and CP asymmetries may enable measurements of the CP-violating parameters in cascade decays at the LHC.

Studying double charm decays ofBu,dandBsmesons in the MSSM withR-parity violation

Motivated by the possible large direct CP asymmetry of B{sub d}{sup 0}{yields}D{sup +}D{sup -} decays measured by the Belle Collaboration, we investigate double charm B{sub u,d} and B{sub s} decays in the minimal supersymmetric standard model with R-parity violation. We derive the bounds on relevant R-parity violating couplings from the current experimental data, which show quite consistent measurements among relative collaborations. Using the constrained parameter spaces, we explore R-parity violating effects on other observables in these decays, which have not been measured or have not been well measured yet. We find that the R-parity violating effects on the mixing-induced CP asymmetries of B{sub d}{sup 0}{yields}D{sup (}*{sup )+}D{sup (}*{sup )-} and B{sub s}{sup 0}{yields}D{sub s}{sup (}*{sup )+}D{sub s}{sup (}*{sup )-} decays could be very large; nevertheless, the R-parity violating effects on the direct CP asymmetries could not be large enough to explain the large direct CP violation of B{sub d}{sup 0}{yields}D{sup +}D{sup -} from Belle. Our results could be used to probe R-parity violating effects and will correlate with searches for direct R-parity violating signals in future experiments.

Superconducting loop quantum gravity and the cosmological constant

We argue that the cosmological constant is exponentially suppressed in a candidate ground state of loop quantum gravity as a nonperturbative effect of a holographic Fermi-liquid theory living on a two-dimensional spacetime. Ashtekar connection components, corresponding to degenerate gravitational configurations breaking large gauge invariance and CP symmetry, behave as composite fermions that condense as in Bardeen–Cooper–Schrieffer theory of superconductivity. Cooper pairs admit a description as wormholes on a de Sitter boundary.

Testing the Kobayashi-Maskawa Theory at the KEK B-factory

Since its establishment, the B-factory at KEK has been operating successfully, achieving successive world records for the luminosity of electron-positron colliders. The factory has also conducted experimental tests related to the Kobayashi-Maskawa theory. First of all, large CP violation was discovered in the B meson system, which is one of the predictions of the model. This was followed by confirmation in various B meson decays. On the other hand, some phenomena have been found which may not be fully explained by the model alone. Expectations are high for clarification using upgraded B-factory(ies).

Episodic circulation and exchange in a wave‐driven coral reef and lagoon system

We examined the role of wave‐driven circulation relative to wind and buoyancy forcing in a coral reef‐lagoon system. Circulation measurements in Paopao Bay, Moorea, French Polynesia, during austral summer show the importance of waves in driving flows over the reef crest, through the lagoon, and out the reef pass. Tides were comparatively weak, due to proximity to amphidromic points, and exhibited an unusual spring‐neap cycle where the major lunar tide modulated the major solar tide, and the overall tidal phase stayed approximately constant. Wind had only a secondary effect compared to surface waves. A simple fluid mass balance indicated rapid flushing of the shallow back reef and export through the reef pass, and a reef capture zone width of ~2.3 km. The reef pass circulation dynamics exhibited two‐layer baroclinic exchange flow when waves were small, which was suppressed during large wave events. The unusually weak tidal forcing provided an opportunity to more closely investigate wave‐driven circulation dynamics. As expected theoretically, there was a wave‐driven setup of the free surface across the shallow lagoon, which drove a highly frictional flow, evident by a large drag coefficient CP ~ 0.1. Diverging from extant theory, the observed setup varied strongly with significant wave height and period. Overall, the circulation and exchange between this coral reef system and the adjacent open ocean were largely determined by episodic remote‐forcing events and differed significantly from periodic tidal‐exchange mechanisms.

NonzeroUe3,CPviolation, and leptogenesis in a seesaw type softly brokenA4symmetric model

We have shown that nonzero U{sub e3} is generated in a seesaw type softly broken A{sub 4} symmetric model through a single parameter perturbation in m{sub D} in a single element. We have explored all possible 9 cases to study the neutrino mixing angles considering the best fitted values of {delta}m{sub {center_dot}}{sup 2} and {delta}m{sub atm}{sup 2} with all parameters real. We have extended our analysis for the complex case and demonstrated large low energy CP violation (J{sub CP}{approx_equal}10{sup -2}) and m{sub ee} in addition to mixing and mass pattern. We have also investigated leptogenesis and for a reasonable choice of model parameters compatible with low energy data, the Wilkinson Microwave Anisotropy Probe (WMAP) value of baryon asymmetry 6x10{sup -10} is obtained for right-handed neutrino mass scale M{sub 0}{approx_equal}10{sup 13} GeV. We have obtained a relation among the phases responsible for leptogenesis and have shown that those phases also have correlations with low energy CP violating phases.

Source dynamics from deuteron and anti-deuteron measurements in Au+Au collisions at GeV in PHENIX

The production of deuterons and anti-deuterons in the transverse momentum range 1.1 <pT< 5.0 GeV/c at mid-rapidity in Au+Au collisions at GeV has been studied by PHENIX for six different centralities. The coalescence of neutrons and protons into deuterons as a function of pT and Npart has been studied. The large RCP of deuterons at intermediate pT is consistent with neutron production having similar centrality dependence to that of protons.

CPviolation in the secluded U(1)′-extended MSSM

We study the Higgs sector of the secluded $U(1)'$-extended MSSM (sMSSM) focusing on CP violation. Using the one-loop effective potential that includes contributions from quarks and squarks in the third generation, we search for the allowed region under theoretical and experimental constraints. It is found that the possible region for the electroweak vacuum to exist is quite limited, depending on the parameters in the model. The masses and couplings of the Higgs bosons are calculated with/without CP violation. Even at the tree level, CP violation is possible by complex soft SUSY breaking masses. Similar to the CPX scenario in the MSSM, the scalar-pseudoscalar mixing enables the lightest Higgs boson mass to become smaller than the $Z$ boson mass while the coupling with the $Z$ boson is sufficiently suppressed to avoid the LEP experimental constraints. However, unlike the CPX scenario, large $\mu$ and $A$ are not required for the realization of large CP violation. The typical spectrum of the SUSY particles is thus different. We also investigate the possible upper bound of the lightest Higgs boson in the case of spontaneous CP violation. The maximal value of it can reach above 100 GeV with maximal CP-violating phases.

Constraints fromD−D¯mixing in supersymmetric left-right symmetric models

We study the constraint arising from the recently observed $D\mathrm{\text{\ensuremath{-}}}\overline{D}$ mixing in the context of supersymmetric models with left-right symmetry. In these models, the supersymmetric contributions in the mixing amplitudes of $D\mathrm{\text{\ensuremath{-}}}\overline{D}$, $K\mathrm{\text{\ensuremath{-}}}\overline{K}$ and $B\mathrm{\text{\ensuremath{-}}}\overline{B}$ are all correlated. We compare the constraint from the $D\mathrm{\text{\ensuremath{-}}}\overline{D}$ mixing with the $K\mathrm{\text{\ensuremath{-}}}\overline{K}$ mixing and find that the $D\mathrm{\text{\ensuremath{-}}}\overline{D}$ mixing constrains the maximal supersymmetric contribution to the ${B}_{s}\mathrm{\text{\ensuremath{-}}}{\overline{B}}_{s}$ mixing amplitude. The maximal supersymmetric contribution can allow a large CP phase of ${B}_{s}\mathrm{\text{\ensuremath{-}}}{\overline{B}}_{s}$ mixing which agrees with the recent measurement of the CP asymmetry of ${B}_{s}\ensuremath{\rightarrow}J/\ensuremath{\psi}\ensuremath{\phi}$ decay.

Neutrino oscillation observables from mass matrix structure

We present a systematic procedure to establish a connection between complex neutrino mass matrix textures and experimental observables, including the Dirac CP phase. In addition, we illustrate how future experimental measurements affect the selection of textures in the (θ13,δCP)-plane. For the mixing angles, we use generic assumptions motivated by quark–lepton complementarity. We allow for any combination between Uℓ and Uν, as well as we average over all present complex phases. We find that individual textures lead to very different distributions of the observables, such as to large or small leptonic CP violation. In addition, we find that the extended quark–lepton complementarity approach motivates future precision measurements of δCP at the level of θC≃11°.

Exploring CP violation and penguin effects through B0 d→D+D- and B0 s→D+ sD- s

The decay B0 d→D+D- offers an interesting probe of CP violation, but it requires control of penguin effects, which can be done through B0 s→D+ sD- s by means of the U-spin flavour symmetry of strong interactions. Recently, the Belle collaboration reported indications of large CP violation in the B0 d decay, which were, however, not confirmed by BaBar, and first signals of the B0 s channel were observed at the Tevatron. In view of these developments and the quickly approaching start of the LHC, we explore the allowed region in observable space for CP violation in B0 d→D+D-, perform theoretical estimates of the relevant hadronic penguin parameters and observables, and we address questions both about the most promising strategies for the extraction of CP-violating phases and about the interplay with other measurements of CP violation and the search for new physics. As far as the latter aspect is concerned, we point out that the B0 q→Dq +D- q system provides a setting for the determination of the B0 q–B0 q mixing phases (q∈{d,s}) that is complementary to the conventional B0 d→J/ψKS and B0 s→J/ψφ modes with respect to possible new-physics effects in the electroweak penguin sector.