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C. Q. Geng

Publications and source records attributed to C. Q. Geng.

At least 55 records · Page 3Linked to original sources
arXiv2014

Semileptonic $B^-\to f_0(1710\,,1500\,,1370) e^-\bar ν_e$ decays

We study the semileptonic decays of $B^-\to f_0(1710\,,1500\,,1370) e^-\bar ν_e$, in which the three $f_0$ states mix with glueball, $\bar s s$ and $(\bar u u+\bar d d)/\sqrt 2$ states, respectively. By averaging the mixings fitted in the literature, we find that the branching ratios of $B^-\to f_0 e^-\bar ν_e$ are $O(10^{-6})$, $O(10^{-6})$ and $O(10^{-5})$, respectively, which can be simultaneously observed in experiments at $B$ factories. The large predicted branching rate for $B^-\to f_0(1370) e^-\bar ν_e$ would provide a clean mode to directly observe the $f_0(1370)$ state.

hep-ph↗
arXiv2014

Possibly New Charmed Baryon States from $\bar B^0\to p\bar p D^{0}$ Decay

We examine the invariant mass spectrum of $D^{0}p$ in $\bar B^0\to p\bar p D^{0}$ decay measured by BABAR and find that through the 2-step processes of $\bar B^0\to {\bf B_c^+}(\to D^{0} p)\bar p$, where ${\bf B_c}$ denotes a charmed baryon state, some of the peaks can be identified with the established $Σ_c(2800)^+$, $Λ_c(2880)^+$ and $Λ_c(2940)^+$. Moreover, in order to account for the measured spectrum, it is necessary to introduce a new charmed baryon resonance with $(m,\,Γ)=(3212\pm 20,\,167\pm 34)$ MeV.

hep-ph↗
arXiv2013

Identifying Glueball at 3.02 GeV in Baryonic $B$ Decays

We examine the nature of the unknown enhancement around 3 GeV observed by the BABAR collaboration in the $m_{p\bar p}$ spectrum of the $\bar B^0\to p\bar p D^0$ decay. Suspecting that the peak is a resonance, which can be neither identified as a charmonium state, such as $η_c$ or $J/ψ$, nor classified as one of the light-flavor mesons, we conclude that it corresponds to a glueball fitted as X(3020) with $(m_X,\;Γ_X)=(3020\pm 8,\; 107\pm 30)\;\text{MeV}$, which could be the first glueball state above 3 GeV. This state also appears in the $m_{p\bar p}$ spectrum of the $\bar B^0\to p\bar p D^{*0}$ decay.

hep-ph↗
arXiv2012

Rare $B^-\toΛ\bar{p}ν\barν$ decay

We study the four-body semileptonic baryonic decay of $B^-\to Λ\bar pν\bar ν$ in the standard model. We find that the decay branching ratio is $(7.9\pm 1.9)\times 10^{-7}$. Similar to the rare decays of $B^-\to K^{(*)-}ν\bar ν$, this baryonic decay of $B^-\to Λ\bar pν\bar ν$ is also sensitive to new physics and accessible to the future $B$ factories.

hep-ph↗
arXiv2012

Large-scale magnetic fields from inflation due to a $CPT$-even Chern-Simons-like term with Kalb-Ramond and scalar fields

We investigate the generation of large-scale magnetic fields due to the breaking of the conformal invariance in the electromagnetic field through the $CPT$-even dimension-six Chern-Simons-like effective interaction with a fermion current by taking account of the dynamical Kalb-Ramond and scalar fields in inflationary cosmology. It is explicitly demonstrated that the magnetic fields on 1Mpc scale with the field strength of $\sim 10^{-9}$G at the present time can be induced.

astro-ph.CO↗
arXiv2011

Semileptonic $B-\to p\bar{p} \ell-\barν_\ell$ decays

We study the four-body exclusive semileptonic baryonic $\bar B$ decays of $B^-\to p\bar p \ell^- \barν_{\ell}$ ($\ell=e,μ,τ$) in the standard model. We find that their decay branching ratios are about $(1.0, 1.0,0.5)\times 10^{-4}$, respectively. In particular, the electron mode is close to the corresponding CLEO's upper limit of $5.2\times 10^{-3}$, while all results are about one or two orders of magnitude larger than the previous estimated values for the inclusive modes of $\bar B\to {\bf B\bar B'}\ell \bar ν$. Clearly, both B-factories of Belle and BaBar should be able to observe these exclusive four-body modes.

hep-ph↗
arXiv2011

Localizing fields on brane in magnetized backgound

To localize the scalar, fermion, and abelian gauge fields on our 3-brane, a simple mechanism with a hypothetical "magnetic field" in the bulk is proposed. This mechanism is to treat all fields in the equal footing without ad hoc consideration. In addition, the machanism can be easily realized in a flat dimension six Minkowski space and it works even in the weak coupling limit.

hep-th↗
arXiv2011

Study of $\bar B\to Λ\bar p\,ρ(ϕ)$ and $\bar B\to Λ\bar Λ\bar K^{*}$

We examine the three-body baryonic $\bar B\to {\bf B\bar B'}V$ decays with $V$ vector mesons in the standard model. We can simultaneously explain the recent experimental data on the decays of $B^-\to Λ\bar p \,ρ^0$ and $\bar B\to Λ\bar Λ\bar K^{*}$ based on the QCD counting rules and SU(3) flavor symmetry. We also predict that the decay branching ratios of $\bar B^0\to Λ\bar p \,ρ^+$ and $B^-\to Λ\bar p \,ϕ$ are 3.0 and $1.5\times 10^{-6}$, respectively, which are promising to be observed by BELLE and BABAR at the $B$ factories.

hep-ph↗
arXiv2011

Signatures of Dark Matter in Inert Triplet Models

In this talk, we will review the signatures of dark matter in two inert triplet models. For the first model with the hypercharge Y=0, the dark matter mass around 5.5 TeV is favored by both the WMAP data and the direct detection. In contrast, for the second model of Y=2, it is excluded by the direct detection experiments although dark matter with its mass around 2.8 TeV is allowed by WMAP.

hep-ph↗
arXiv2011

Dark Matter in Inert Triplet Models

We study the inert triplet models, in which the standard model (SM) is extended to have a new SU(2)L triplet scalar (Y=0 or 2) with an Z2 symmetry. We show that the neutral component of the triplet can be a good dark matter candidate. In particular, for the hypercharge Y=0 triplet model, the WMAP data favors the region where the dark matter mass is around 5.5 TeV, which is also consistent with the direct detection experiments. In contrast, for the Y=2 model, although dark matter with its mass around 2.8 TeV is allowed by WMAP, it is excluded by the direct detection experiments because the spin-independent cross section is enhanced by the Z mediated tree-level scattering process.

hep-ph↗
arXiv2010

Relating Neutrino Masses by dilepton modes of Doubly Charged Scalars

We study a model with Majorana neutrino masses generated through doubly charged scalars at two-loop level. We give explicit relationships between the neutrino masses and the same sign dilepton decays of the doubly charged scalars. In particular, we demonstrate that at the tribimaximal limit of the neutrino mixings, the absolute neutrino masses and Majorana phases can be extracted through the measurements of the dilepton modes at colliders.

hep-ph↗
arXiv2010

mu-tau symmetry in Zee-Babu model

We study the Zee-Babu two-loop neutrino mass generation model and look for a possible flavor symmetry behind the tri-bimaximal neutrino mixing. We find that there probably exists the mu-tau symmetry in the case of the normal neutrino mass hierarchy, whereas there may not be in the inverted hierarchy case. We also propose a specific model based on a Froggatt-Nielsen-like $Z_5$ symmetry to naturally accomplish the mu-tau symmetry on the neutrino mass matrix for the normal hierarchy case.

hep-ph↗
arXiv2010

Quark Masses and Mixings with Hierarchical Friedberg-Lee Symmetry

We consider the Friedberg-Lee symmetry for the quark sector and show that the symmetry closely relates to both quark masses and mixing angles. We also extend our scheme to the fourth generation quark model and find the relation $|V_{tb^{'}}| \simeq |V_{t^{'}b}| \simeq m_b/m_{b^{'}}< λ^2$ with $λ\simeq0.22$ for $m_b=4.2\ \gev$ and $m_{b^{'}}>199\ \gev$.

hep-ph↗
arXiv2010

Leptogenesis with Friedberg-Lee Symmetry

We consider the $μ-τ$ symmetric Friedberg-Lee (FL) symmetry for the neutrino sector and show that a specific FL translation leads to the tribimaximal mixing pattern of the Maki-Nakagawa-Sakata (MNS) matrix. We also apply the symmetry to the type-I seesaw framework and address the baryon asymmetry of the universe through the leptogenesis mechanism. We try to establish a relation between the net baryon asymmetry and CP phases included in the MNS matrix.

hep-ph↗
arXiv2009

Leptogenesis in a model with Friedberg-Lee symmetry

We study the matter-antimatter asymmetry through the leptogenesis mechanism in a specific model with the Friedberg-Lee (FL) symmetry.We relate the leptogenesis with the CP violating Dirac and Majorana phases in the Maki-Nakagawa-Sakata leptonic mixing matrix and illustrate the net baryon asymmetry of the universe in terms of these phases.

hep-ph↗
arXiv2009

Constraints on the Timeon Model

The timeon model recently proposed by Friedberg and Lee has a potential problem of flavor changing neutral currents (FCNCs) if the mass of the timeon is small. In order to avoid, we introduce a small dimensionless parameter to suppress FCNCs. Even in this case, we find that the timeon mass must be larger than 151 GeV to satisfy all the constraints from processes involving FCNCs in the quark sectors. We also extend the timeon model to the lepton sector and examine the leptonic processes.

hep-ph↗
arXiv2009

Searching for doubly charged Higgs bosons in Möller scattering by resonance effects at linear $e^-e^-$ collider

We discuss the parity-violating left-right asymmetries (LRAs) in Möller scattering at the International Linear Collider (ILC) induced by doubly charged Higgs bosons in models with $SU(2)_L$ triplet and singlet scalar bosons, which couple to the left- and right-handed charged leptons, respectively. These bosons are important in the scenarios for the generation of the neutrino mass. We demonstrate that the contributions to the LRAs from the triplet and singlet bosons are opposite to each other. In particular, we show that the doubly charged Higgs boson from the singlet scalar can be tested at the ILC by using the resonance effect.

hep-ph↗