Combining the up-to-date experimental information on $B\toπK, πK^{\ast}$ and $ρK$ decays, we revisit the decay rates and CP asymmetries of these decays within the framework of QCD factorization. Using an infrared finite gluon propagator of Cornwall prescription, we find that the time-like annihilation amplitude could contribute a large strong phase, while the space-like hard spectator scattering amplitude is real. Numerically, we find that all the branching ratios and most of the direct CP violations, except $A_{CP}(B^{\pm}\to K^{\pm}π^{0})$, agree with the current experimental data with an effective gluon mass $m_g\simeq0.5 {\rm GeV}$. Taking the unmatched difference in direct CP violations between $B\toπ^{0} K^{\pm}$ and $π^{\mp}K^{\pm}$ decays as a hint of new physics, we perform a model-independent analysis of new physics contributions with a set of $\bar{s}(1+γ_{5})b\otimes\bar{q}(1+γ_{5})q$ (q=u,d) operators. Detail analyses of the relative impacts of the operators are presented in five cases. Fitting the twelve decay modes, parameter spaces are found generally with nontrivial weak phases. Our results may indicate that both strong phase from annihilation amplitude and new weak phase from new physics are needed to resolve the $πK$ puzzle. To further test the new physics hypothesis, the mixing-induced CP violations in $B\toπ^{0}K_{S}$ and $ρ^{0}K_{S}$ are discussed and good agreements with the recent experimental data are found.
After a brief review of the minimal flavour violation hypothesis and its implementation in the MSSM, the most general parametrisation of the soft supersymmetry-breaking terms by means of the charged lepton and neutrino spurions is constructed. Thereby a type I seesaw mechanism is assumed to generate neutrino masses. This expansion introduces several new CP-violating phases, whose effects on the leptonic electric dipole moments are investigated.
The Minimal Lepton Flavour Violation (MLFV) framework is discussed after the recent indication for CP violation in the leptonic sector. Among the three distinct versions of MLFV, the one with degenerate right-handed neutrinos will be disfavoured, if this indication is confirmed. The predictions for leptonic radiative rare decays and muon conversion in nuclei are analysed, identifying strategies to disentangle the different MLFV scenarios. The claim that the present anomalies in the semi-leptonic $B$-meson decays can be explained within the MLFV context is critically re-examined concluding that…
Precision measurement of the neutrino mixing parameters and the determination of mass hierarchy are the primary goals of the present and upcoming neutrino experiments. In this work, we study the sensitivity of T2K,NO$ν$A and LBNE experiments to discover leptonic CP violation and the determination of neutrino mass hierarchy. We obtain the correlation between the CP violating phase $δ_{CP}$ and the mixing angles $θ_{13}$, $θ_{23}$ and the sensitivity to determine the octant of atmospheric mixing angle $θ_{23}$. The entire analysis is done for a total 10 years (5$ν$+ 5$\bar ν$) of running of T2K,…
We revisit the minimal supersymmetric SU(5) grand unified theory with three right-handed neutrinos in which universality conditions for soft-supersymmetry breaking parameters are imposed at an input scale above the unification scale. If the Majorana masses for the neutrinos are around $10^{15}$ GeV, large mixing angles and phases in the neutrino sector lead to flavor-violation and CP-violation in the right-handed down squark and left-handed slepton sectors. Since the observed Higgs boson mass and the proton decay constraints indicate sfermions have masses larger than a few TeV, flavor and CP c…
In view of the recent measurement of reactor mixing angle $θ_{13}$ and updated limit on $BR(μ\to e γ)$ by the MEG experiment, we re-examine the charged lepton flavor violations in a framework of supersymmetric type II seesaw mechanism. Supersymmetric type II seesaw predicts strong correlation between $BR(μ\to e γ)$ and $BR(τ\to μγ)$ mainly in terms of the neutrino mixing angles. We show that such a correlation can be determined accurately after the measurement of $θ_{13}$. We compute different factors which can affect this correlation and show that the mSUGRA-like scenarios, in which slepton m…
In the context of GUT baryogenesis models, a well-known theorem asserts that CPT conservation and the unitarity of S-matrix require that the lowest order contribution that leads to the generation of a non-zero net CP-violation via the decay of a heavy particle must be to $\mathcal{O}({α_\slashed{B}}^3)$, where $α_\slashed{B}$ is a baryon number (B) violating coupling. We revisit this theorem (which holds for lepton number (L) violation, and hence for leptogenesis as well) and examine its implications for models where the particle content allows the heavy particle to also decay via modes which …
We calculate the branching ratios and CP asymmetries of the $B \to πρ$, $πω$ decays in the perturbative QCD factorization approach up to the next-to-leading-order contributions. We find that the next-to-leading-order contributions can interfere with the leading-order part constructively or destructively for different decay modes. Our numerical results have a much better agreement with current available data than previous leading-order calculations, e.g., the next-to-leading-order corrections enhance the $B^0\rightarrow π^0ρ^0$ branching ratios by a factor 2.5, which is helpful to narrow the ga…
Planck scale lepton number violation is an interesting and natural possibility to explain non-zero neutrino masses. We consider such operators in the context of Randall-Sundrum (RS1) scenarios. Implementation of this scenario with a single Higgs localized on the IR brane (standard RS1) is not phenomenologically viable as they lead to inconsistencies in the charged lepton mass fits. In this work we propose a set-up with two Higgs doublets. We present a detailed numerical analysis of the fits to fermion masses and mixing angles. This model solves the issues regarding the fermion mass fits but so…
The rare decay $B\to K^\ast( \to Kπ) ν\barν$ is expected to play an important role in searches for physics beyond the Standard Model at the near future $B$-physics experiments. We investigate resonant and non-resonant backgrounds that arise beyond the narrow-width approximation for the $K^\ast$. Non-resonant $B\to Kπν\barν$ decays are analyzed in the region of low hadronic recoil, where $B \to K π$ form factors from Heavy-Hadron-Chiral-Perturbation Theory are available. In a Breit-Wigner-type model interference-induced effects in the $K^*$ signal region are found to be sizable, as large as $20…
One of the main motivations to look beyond the SM is the discrepancy between the theoretical prediction and observation of anomalous magnetic moment of muon. Alleviating this tension between theory and experiment and satisfying the bounds from lepton flavor violation data simultaneously is a challenging task. In this paper, we consider generalised Two Higgs Doublet Model, with a Yukawa structure as a perturbation of Type X Two Higgs Doublet Model. In view of this model, we explore muon anomaly and lepton flavor violation along with constraints coming from B-physics, theoretical constraints, el…
We take a closer look at the recently discussed models of hadrons based on holographic ideas and chiral symmetry breaking in five dimensions. We study the two point correlator in detail and look at the field theoretic properties needed to be satisfied by the correlator. It is shown that the spectral density becomes negative, violating the basic requirements for the Kallen-Lehmann representation. We briefly discuss the implications of this violation of the positivity of the spectral density and also discuss possible origin of such a violation in these models. Put simply this means that such mod…
We have studied charmless two-body B decays involving $η$ and $η'$ in the framework of QCD improved factorization appraoch. The spectator hard scattering mechanism for $η'$ production have been re-examined and extended, which contributions are incorporated consistently into the factorizable leading contributions. It is found that the conventional mechanism would give $Br(B\to η' K)\sim 30\times 10^{-6}$ which agrees with predictions based on naive factorization approaches. With the incorporation of spectator hard scattering mechanism contributions, theoretical predictions are improved much and…
In this letter we revisit the Standard Model predictions for $\mathcal{B}(B\to K^{(\ast)}ν\barν)$ and discuss the opportunities that open up when combining its partial decay rate with that of $B\to K^{(\ast)}\ell\ell$. In the Standard Model a suitable ratio of these two modes can be used to extract $C_9^\mathrm{eff}$, which is essential for a reliable phenomenological analysis of the $B\to K^{(\ast)}\ell\ell$ angular observables. The same ratio also proves to be more sensitive to the presence of New Physics in many plausible extensions of the Standard Model. We also suggest that the separate m…
New physics contributions to the $Z$ penguin are revisited in the light of the recently-reported discrepancy of the direct CP violation in $K\toππ$. Interference effects between the standard model and new physics contributions to $ΔS = 2$ observables are taken into account. Although the effects are overlooked in the literature, they make experimental bounds significantly severer. It is shown that the new physics contributions must be tuned to enhance $\mathcal{B}(K_L \to π^{0} ν\barν)$, if the discrepancy of the direct CP violation is explained with satisfying the experimental constraints. The…
Revisiting unitarity of single scalar field with non-minimal coupling
Center for Theoretical Physics of the Universe, Institute for Basic Science (IBS)（基础科学研究院宇宙理论物理中心）；Department of Physics, Graduate School of Science, The University of Tokyo（东京大学理学研究科物理学系）；Research Center for the Early Universe (RESCEU), Graduate School of Science, The University of Tokyo（东京大学理学研究科早期宇宙研究中心）；Kavli Institute for the Physics and Mathematics of the Universe (WPI), UTIAS, The University of Tokyo（东京大学汤川理论物理研究所 Kavli 宇宙物理数学研究所）；Theory Center, IPNS, KEK（高能加速器研究机构理论物理中心）；Graduate University for Advanced Studies (Sokendai)（综合研究大学院大学）
Within the Standard Model, we investigate the CP violations and the $K_S^0-K_L^0$ asymmetries in $D^{\pm}\rightarrow K^{\ast}(892)^{0} π^{\pm} + \bar{K}^{\ast }(892)^{0}π^{\pm}\rightarrow K_{S,L}^{0}π^0 π^{\pm}$ decays basing on the factorization-assisted topological-amplitude (FAT) approach and the topological amplitude (TA) approach of Cheng and Chiang [Phys. Rev. D 104, 073003 (2021).]. We find that the CP violations in these decays $A_{CP}^{K_{S,L}^0}$ can exceed the order of $10^{-3}$ in the two approaches and consist of three parts: the indirect CP violations in $K^0 -\bar{K}^0$ mixing $…
We revisit the case of a light neutralino LSP in the framework of the MSSM. We consider a model with eleven free parameters. We show that all scenarios where the annihilation of light neutralinos rely mainly on the exchange of a light pseudoscalar are excluded by direct detection searches and by Fermi measurements of the gamma-flux from dwarf spheroidal galaxies. On the other hand, we find scenarios with light sleptons that satisfy all collider and astroparticle physics constraints. In this case, the lower limit on the LSP mass is 12.6 GeV. We discuss how the parameter space of the model will …
In the last few years, the ratios $R_{D^{(*)}}$ and of $R_{K^{(*)}}$ have reportedly exhibited significant deviations from the relevant Standard Model predictions, hinting towards a possible violation of Lepton Flavor Universality and a window to New Physics. We investigate to what extent the inclusion of R-parity violating couplings in the Minimal Supersymemtric Standard Model can provide a better fit to the anomalies simultaneously. We perform this analysis employing an approximate, non-abelian $\mathcal{G}_f=U(2)_q \times U(2)_\ell$ flavour symmetry, which features a natural explanation of …
In recent years, several deviations from the Standard Model predictions in semileptonic decays of $B$-meson might suggest the existence of new physics which would break the lepton-flavour universality. In this work, we have explored the possibility of using muon sneutrinos and right-handed sbottoms to solve these $B$-physics anomalies simultaneously in $R$-parity violating minimal supersymmetric standard model. We find that the photonic penguin induced by exchanging sneutrino can provide sizable lepton flavour universal contribution due to the existence of logarithmic enhancement for the first…
Direct CP violation in the hadronic charm decays provides a good testing ground for the Kobayashi-Maskawa mechanism in the Standard Model. Any significant deviations from the expectation would be indirect evidence of physics beyond the Standard Model. In view of improved measurements from LHCb and BESIII experiments, we re-analyze the Cabibbo-favored $D \to P\!P$ and $V\!P$ decays in the topological diagram approach. By assuming certain SU(3)-breaking effects in the tree-type amplitudes, we make predictions for both branching fractions and CP asymmetries of the singly Cabibbo-suppressed decay …
It has been shown recently that the anomalies observed in $\bar B\to D^{(\ast)}τ\barν_τ$ and $\bar B\to \bar K\ell^+\ell^-$ decays could be resolved with just one scalar leptoquark. Fitting to the current data on $R(D^{(\ast)})$ along with acceptable $q^2$ distributions in $\bar B\to D^{(\ast)}τ\barν_τ$ decays, four best-fit solutions for the operator coefficients have been found. In this paper, we explore the possibilities of how to discriminate these four solutions. Firstly, we find that two of them are already excluded by the decay $B_c^-\to τ^-\barν_τ$, because the predicted decay widths h…
It is well known that a fundamental theorem of Quantum Field Theory (QFT) set in at spacetime ensures the CPT invariance of the theory. This symmetry is strictly connected to the Lorentz covariance, and consequently to the fundamental structure of spacetime. Therefore it may be interesting to investigate the possibility of departure from this fundamental symmetry, since it can furnish a window to observe possible effects of a more fundamental quantum gravity theory in a "lower energy limit". Moreover, in the past, the inquiry of symmetry violations provided a starting point for new physics dis…
Motivated by the recent measurements of non-leptonic $\bar{B}_s^0$ decays by CDF and LHCb collaborations, especially the large ${\cal B}(\bar{B}_s^0\toπ^+π^-)$, we revisit the hard spectator and annihilation corrections in $\bar{B}_s^0$ decays within QCD factorization approach with two schemes for the possible parameters for the known end-point divergence appeared in the estimation of the hard spectator and annihilation diagrams. The first one is to conservatively estimate the possible contributions by parameterization (scheme I); another one uses an infrared finite gluon propagator (scheme II…
We investigate the time-evolutions of angular distributions for $B_s$ decays into final states that are admixtures of CP-even and CP-odd configurations. A sizable lifetime difference between the $B_s$ mass eigenstates allows a probe of CP violation in time-dependent untagged angular distributions. Interference effects between different final state configurations of $B_s\to D^{*+}_s D^{*-}_s$, $J/ψϕ$ determine the Wolfenstein parameter $η$ from untagged data samples, or -- if one uses $|V_{ub}|/|V_{cb}|$ as an additional input -- the notoriously difficult to measure CKM angle $γ$. Another deter…
Revisiting Very High Energy Gamma-Ray Absorption in Cosmic Propagation under the Combined Effects of Axion-Like Particles and Lorentz Invariance Violation
Yuxi Normal University（玉溪师范学院）；Yunnan Observatory, Chinese Academy of Sciences（中国科学院云南天文台）；Key Laboratory for the Structure and Evolution of Celestial Objects, Chinese Academy of Sciences（中国科学院天体结构与演化重点实验室）；Hunan Normal University（湖南师范大学）；Kunming University of Science and Technology（昆明理工大学）；Shaoguan University（韶关学院）
Decays of the kind $B_s\to D_s^{\pm}K^\mp, D_s^{\ast\pm}K^\mp, ...$ and $B_d\to D^{\pm}π^\mp, D^{\ast\pm}π^\mp, ...$ allow us to probe $ϕ_s+γ$ and $ϕ_d+γ$, respectively, involving the angle $γ$ of the unitarity triangle and the $B^0_q$--$\bar B^0_q$ mixing phases $ϕ_q$ ($q\in\{d,s\}$). Analysing these modes in a phase-convention-independent way, we find that their mixing-induced observables are affected by a subtle $(-1)^L$ factor, where $L$ denotes the angular momentum of the $B_q$ decay products, and derive bounds on $ϕ_q+γ$. Moreover, we emphasize that ``untagged'' rates are an important in…
Attributing the recent CLEO discovery of $B \to η' + X_s$ to originate (primarily) from the fragmentation of an off-shell gluon ($g^*$) via $b \to s + g^*$, $g^* \to g + η'$, we emphasize that many such states ($X_g$) should materialize. Indeed the hadronic fragments ($X_g$) of $g^*$ states are closely related to those seen in $ψ\to γ(ϕ, ω) + X_g$. A particular final state of considerable interest is $X_g=K^+K^-$. Signals from such states in $B$ decays can be combined to provide a very sensitive search for CP violating phase(s) from non-standard physics. The method should work even if the cont…
The decays $K^{\ast}(892)\rightarrow K_{S,L}^{0}π$ can be used to study CP violation and CPT violation. The $K^{\ast}(892)$ (hereinafter referred to as $K^{\ast}$) meson can be produced via $J/ψ$ decays at BESIII. In this paper, we study CP violation and $K_S^0-K_L^0$ asymmetry in the $J/ψ$ decays involving the $K^{\ast}$ meson in the final states and obtain the following results \begin{align} {\mathcal A}_{CP}\left(J/ψ\rightarrow K^{\ast}f_{J/ψ}\rightarrow K^0_{S}πf_{J/ψ}\right)=\left(3.64\pm0.04\right)\times 10^{-3},\nonumber\\ {\mathcal A}_{CP}\left(J/ψ\rightarrow K^{\ast}f_{J/ψ}\rightarrow…
It is found that the atmospheric neutrino mixing angle of θ_{atm} is determined to be \tanθ_{atm}=Im(B)/Im(C) for B=M_{ν_eν_μ} and C=M_{ν_eν_τ}, where M_{ij} is the ij element of M^\dagger_νM_νwith M_νas a complex symmetric neutrino mass matrix in the (ν_e, ν_μ, ν_τ)-basis. Another mixing angle, θ_{13}, defined as U_{e3} = \sinθ_{13}e^{-iδ} is subject to the condition: \tan 2θ_{13} \propto |\sinθ_{atm}B+\cosθ_{atm}C| and the CP-violating Dirac phase of δis identical to the phase of \sinθ_{atm}B^\ast+\cosθ_{atm}C^\ast. The smallest value of |\sin θ_{13}| is achieved at \tanθ_{atm}=-Re(C)/Re(B) …
Astroparticle physics has recently reached a new status of precision due to the construction of new observatories, operating innovative technologies and the detection of large numbers of events and sources. The precise measurements of cosmic and gamma rays can be used as a test for fundamental physics, such as the Lorentz invariance violation (LV). Although LV signatures are expected to be small, the very high energies and long distances that astrophysical sources involve, lead to an unprecedented opportunity for this task. In this summary, exclusion limits results are presented from different…
We explore the limits on lepton-flavor universality (LFU) violation in theories where the hierarchy problem is solved by means of a warped extra dimension. In those theories LFU violation, in fermion interaction with Kaluza-Klein modes of gauge bosons, is provided ab initio when different flavor of fermions are differently localized along the extra dimension. As this fact arises from the mass pattern of quarks and leptons, LFU violation is natural in this class of theories. We analyze the experimental data pointing towards LFU violation, as well as the most relevant electroweak and flavor obse…
Within the framework of QCD factorization (QCDF), we consider two different types of power correction effects in order to resolve the CP puzzles and rate deficit problems with penguin-dominated two-body decays of B mesons and color-suppressed tree-dominated $π^0π^0$ and $ρ^0π^0$ modes: penguin annihilation and soft corrections to the color-suppressed tree amplitude. We emphasize that the electroweak penguin solution to the $B\to Kπ$ CP puzzle via New Physics is irrelevant for solving the CP and rate puzzles related to tree-dominated decays. While some channels e.g. $K^-π^+,K^-ρ^0,π^+π^-,ρ^\pmπ…
We perform a systematic study of the fermionic DM absorption interactions on electron target in the context of effective field theory. The fermionic DM absorption is not just sensitive to sub-MeV DM with efficient energy release, but also gives a unique signature with clear peak in the electron recoil spectrum whose shape is largely determined by the atomic effects. Fitting with the Xenon1T and PandaX-II data prefers DM mass at $m_χ= 59$keV and 105keV, respectively, while the cut-off scale is probed up to around 1TeV. The DM overproduction in the early Universe, the invisible decay effect on t…
Starting from the general effective hamiltonian relevant to the $b\to s$ transitions, we derive the expressions for the full angular distributions of the $B \to K^{(\ast )} \ell_1 \ell_2$ decay modes, as well as for ${\cal B}(B_s \to \ell_1\ell_2 )$ ($\ell_1\neq \ell_2$). We point out the differences in the treatment of the lepton flavor violating modes with respect to the lepton flavor conserving ones. Concerning the relevant Wilson coefficients we evaluate them in two different scenarios: (i) The (pseudo-)scalar coefficients are obtained using the (pseudo-)scalar coupling extracted from the …
