arXiv subjects

Bo-Qiang Ma

Publications and source records attributed to Bo-Qiang Ma.

At least 145 records · Page 8Linked to original sources

arXiv2012

A prediction of neutrino mixing matrix with CP violating phase

The latest experimental progress have established three kinds of neutrino oscillations with three mixing angles measured to rather high precision. There is still one parameter, i.e., the CP violating phase, missing in the neutrino mixing matrix. It is shown that a replay between different parametrizations of the mixing matrix can determine the full neutrino mixing matrix together with the CP violating phase. From the maximal CP violation observed in the original Kobayashi-Maskawa (KM) scheme of quark mixing matrix, we make an Ansatz of maximal CP violation in the neutrino mixing matrix. This leads to the prediction of all nine elements of the neutrino mixing matrix and also a remarkable prediction of the CP violating phase $δ_{\rm CK}=(85.48^{+4.67(+12.87)}_{-1.80(-4.90)})^\circ$ within $1σ(3σ)$ range from available experimental information. We also predict the three angles of the unitarity triangle corresponding to the quark sector for confronting with the CP-violation related measurements.

hep-ph↗

arXiv2012

Mass effect in polarization investigation at BEPC/BES and the B-factory

We consider the annihilation process of an electron-positron pair into a pair of heavier fermions when the initial electron and position beams are polarized. By calculating the polarization of the final-state particles, we discuss in detail the effect due to the produced particle masses in the $τ$-charm energy region at BEPC/BES, and also compare the effect with that at the B-factory. Such a study is useful for the design of possible polarization investigation at the BEPC/BES facility and the B-factory.

hep-ph↗

arXiv2012

Quark-lepton complementarity revisited

We reexamine the quark-lepton complementarity (QLC) in nine angle-phase parametrizations with the latest result of a large lepton mixing angle $\vartheta_{13}$ from the T2K, MINOS and Double Chooz experiments. We find that there are still two QLC relations satisfied in P1, P4 and P6 parametrizations, whereas only one QLC relation holds in P2, P3, P5 and P9 parametrizations separately. We also work out the corresponding reparametrization-invariant forms of the QLC relations and check the resulting expressions with the experimental data. The results can be viewed as a check of the validity of the QLC relations, as well as a new perspective into the issue of seeking for the connection between quarks and leptons.

hep-ph↗

arXiv2012

Heavy quarkonium 2S states in light-front quark model

We study the charmonium 2S states $ψ'$ and $η_c'$, and the bottomonium 2S states $Υ'$ and $η_b'$, using the light-front quark model and the 2S state wave function of harmonic oscillator as the approximation of the 2S quarkonium wave function. The decay constants, transition form factors and masses of these mesons are calculated and compared with experimental data. Predictions of quantities such as Br$(ψ' \to γη_c')$ are made. The 2S wave function may help us learn more about the structure of these heavy quarkonia.

hep-ph↗

arXiv2012

New perspective on space and time from Lorentz violation

I present a brief review on space and time in different periods of physics, and then talk on the nature of space and time from physical arguments. I discuss the ways to test such a new perspective on space and time through searching for Lorentz violation in some physical processes. I also make an introduce to a newly proposed theory of Lorentz violation from basic considerations.

hep-ph↗

arXiv2012

Superluminal Neutrinos in the Minimal Standard Model Extension

Most recently, the measurement of the neutrino velocity with the OPERA detector in the CNGS beam shows unexpected indication, that the muon neutrino velocity, $v_ν$, exceeds the velocity of light in the vacuum, $c$, which is obviously in contradiction with the most basic hypothesis of modern physics. Within the framework of minimal Standard Model Extension, we discuss the modified dispersion relation and consequently the velocity-energy relation of muon neutrinos. The simplified models are fit to the OPERA data, Fermilab experiment and MINO data. We find that minimal Standard Extension can describe these long baseline superluminal neutrinos to a good accuracy. For the well-known tension between the OPERA measurement and the Supernova 1987A neutrino observation, we discussed two ways out of the contradiction.

hep-ph↗

arXiv2012

On self-complementarity relations of neutrino mixing

With the latest results of a large mixing angle $θ_{13}$ for neutrinos by the T2K, MINOS and Double Chooz experiments, we find that the self-complementarity (SC) relations agree with the data in some angle-phase parametrizations of the lepton mixing matrix. There are three kinds of self-complementarity relations: (1) $\vartheta_i+\vartheta_j=\vartheta_k=45^\circ$; (2) $\vartheta_i+\vartheta_j=\vartheta_k$; (3) $\vartheta_i+\vartheta_j=45^\circ$ (where $i$, $j$, $k$ denote the mixing angles in the angle-phase parametrizations). We present a detailed study on the self-complementarity relations in nine different angle-phase parametrizations, and also examine the explicit expressions in reparametrization-invariant form, as well as their deviations from global fit. These self-complementarity relations may lead to new perspective on the mixing pattern of neutrinos.

hep-ph↗

arXiv2012

The Phantom of the OPERA: Superluminal Neutrinos

This report presents a brief review on the experimental measurements of the muon neutrino velocities from the OPERA, Fermilab and MINOS experiments and that of the (anti)-electron neutrino velocities from the supernova SN1987A, and consequently on the theoretical attempts to attribute the data as signals for superluminality of neutrinos. Different scenarios on how to understand and treat the background fields in the effective field theory frameworks are pointed out. Challenges on interpreting the OPERA result as a signal of neutrino superluminality are briefly reviewed and discussed. It is also pointed out that a covariant picture of Lorentz violation may avoid the refutation on the OPERA experiment.

hep-ph↗

arXiv2012

The $\cos2ϕ$ azimuthal asymmetry of unpolarized $p\bar{p}$ collisions at Tevatron

We calculate the $\cos2ϕ$ azimuthal asymmetry of the unpolarized $p\bar{p}$ Drell-Yan dilepton production process in the $Z$-resonance region at the Tevatron kinematic domain. Such an azimuthal asymmetry can provide additional information about a spin-related new parton distribution function, i.e., the Boer-Mulders function of the proton, compared to the $pp$ process. Therefore the available data of unpolarized proton-antiproton collision at Tevatron can contribute to our study on the spin structure of the nucleon.

hep-ph↗

arXiv2012

Re-evaluation of neutrino mixing pattern according to latest T2K result

We re-evaluate neutrino mixing patterns according to the latest T2K result for a larger mixing angle $θ_{13}$, and find that the PMNS mixing matrix has larger deviations from bimaximal (BM) and tribimaximal (TB) mixing patterns than previously expected. We also find that several schemes connecting PMNS and CKM mixing matrices can accommodate the latest T2K result nicely. As necessary updates to former works, we make new triminimal expansions of PMNS mixing matrix based on BM and TB mixing patterns. We also propose a new mixing pattern with a self-complementary relation between the mixing angles $θ_{12}^ν + θ_{13}^ν \simeq 45^\circ$, and find such a new mixing pattern in leading order can provide a rather good description of the data.

hep-ph↗

arXiv2011

The CDF dijet excess from intrinsic quarks

The CDF collaboration reported an excess in the production of two jets in association with a $W$. We discuss constraints on possible new particle state interpretations of this excess. The fact of no statistically significant deviation from the SM expectation for {$Z$+dijet} events in CDF data disfavors the new particle explanation. We show that the nucleon intrinsic strange quarks provide an important contribution to the $W$ boson production in association with a single top quark production. Such {$W$+t} single top quark production can contribute to the CDF {$W$+dijet} excess, thus the nucleon intrinsic quarks can provide a possible explanation to the CDF excess in {$W$+dijet} but not in {$Z$+dijet} events.

hep-ph↗

arXiv2011

On the rationality of the OPERA experiment as a signal of Lorentz violation

We show that the superluminal muon neutrinos in the recent OPERA experiment can exist theoretically. The refutation of the OPERA experiment from some theoretical arguments is not universally valid, but resulting from some implicit assumptions. Our argument can accommodate both the OPERA experiment for superluminal neutrinos and the ICARUS experiment of no evidence for the analogues Cherenkov radiation of muon neutrinos from CERN to the LNGS.

hep-ph↗

arXiv2011

Three-dimensional parton distribution functions $g_{1T}$ and $h_{1L}^\perp$ in the polarized proton-antiproton Drell-Yan process

We present predictions of the unweighted and weighted double spin asymmetries related to the transversal helicity distribution $g_{1T}$ and the longitudinal transversity distribution $h_{1L}^\perp$, two of eight leading-twist transverse momentum dependent parton distributions (TMDs) or three-dimensional parton distribution functions (3dPDFs), in the polarized proton-antiproton Drell-Yan process at typical kinematics on the Facility for Antiproton and Ion Research (FAIR). We conclude that FAIR is ideal to access the new 3dPDFs towards a detailed picture of the nucleon structure.

hep-ph↗

arXiv2011

Challenges Confronting Superluminal Neutrino Models

This talk opens the CosPA2011 session on OPERA's superluminal neutrino claim. I summarize relevant observations and constraints from OPERA, MINOS, ICARUS, KamLAND, IceCube and LEP as well as observations of SN1987A. I selectively review some models of neutrino superluminality which have been proposed since OPERA's announcement, focusing on a neutrino dark energy model. Powerful theoretical constraints on these models arise from Cohen-Glashow bremsstrahlung and from phase space requirements for the initial neutrino production. I discuss these constraints and how they might be evaded in models in which the maximum velocities of both neutrinos and charged leptons are equal but only superluminal inside of a dense medium.

hep-ph↗

arXiv2011

Azimuthal asymmetries in single polarized proton-proton Drell-Yan processes

We study the azimuthal asymmetries in proton-proton Drell-Yan processes with one incident proton being transversely or longitudinally polarized. We consider particularly the asymmetries contributed by the leading-twist chiral-odd quark distributions. We analyze the asymmetries with $\sin(2ϕ+ϕ_S)$ and $\sin(2ϕ-ϕ_S)$ modulations in transverse single polarized $p^\uparrow p$ Drell-Yan and $\sin2ϕ$ asymmetries in longitudinal single polarized $p^\rightarrow p$ Drell-Yan at RHIC, J-PARC, E906 (Fermi Lab) and NICA (JINR). We show that the measurements of the asymmetries in those facilities can provide valuable information of the chiral-odd structure of the nucleon both in the valence and sea regions.

hep-ph↗

arXiv2011

New theory of Lorentz violation from a general principle

We report that a general principle of physical independence of mathematical background manifolds brings a replacement of common derivative operators by co-derivative ones. Then we obtain a new Lagrangian for the ordinary minimal standard model with supplementary terms containing the Lorentz invariance violation information measured by a new matrix, denoted as the Lorentz invariance violation matrix. We thus provide a new fundamental theory to study Lorentz invariance violation effects consistently and systematically.

hep-th↗

arXiv2011

Neutrino Oscillations: from Standard and Non-standard Viewpoints

In the standard model of neutrino oscillations, the neutrino flavor states are mixtures of mass-eigenstates, and the phenomena are well described by the neutrino mixing matrix, i.e., the PMNS matrix. I review the recent progress on parametrization of the neutrino mixing matrix. Besides that I also discuss on the possibility to describe the neutrino oscillations by a non-standard model in which the neutrino mixing is caused by the Lorentz violation (LV) contribution in the effective field theory for LV. We assume that neutrinos are massless and that neutrino flavor states are mixing states of energy eigenstates. In our calculation the neutrino mixing parts depend on LV parameters and neutrino energy. The oscillation amplitude varies with the neutrino energy, thus neutrino experiments with energy dependence may test and constrain the Lorentz violation scenario for neutrino oscillation.

hep-ph↗

arXiv2011

B_c meson rare decays in the light-cone quark model

We investigate the rare decays $B_c \rightarrow D_s(1968) \ell \bar{\ell}$ and $B_c\rightarrow D_s^*(2317) \ell \bar{\ell}$ in the framework of the light-cone quark model (LCQM). The transition form factors are calculated in the space-like region and then analytically continued to the time-like region via exponential parametrization. The branching ratios and longitudinal lepton polarization asymmetries (LPAs) for the two decays are given and compared with each other. The results are helpful to investigating the structure of $B_c$ meson and to testing the unitarity of CKM quark mixing matrix. All these results can be tested in the future experiments at the LHC.

hep-ph↗