Non-classical properties and algebraic characteristics of negative binomial states in quantized radiation fields

We study the nonclassical properties and algebraic characteristics of the negative binomial states introduced by Barnett recently. The ladder operator formalism and displacement operator formalism of the negative binomial states are found and the algebra involved turns out to be the SU(1,1) Lie algebra via the generalized Holstein-Primarkoff realization. These states are essentially Peremolov's SU(1,1) coherent states. We reveal their connection with the geometric states and find that they are excited geometric states. As intermediate states, they interpolate between the number states and geometric states. We also point out that they can be recognized as the nonlinear coherent states. Their nonclassical properties, such as sub-Poissonian distribution and squeezing effect are discussed. The quasiprobability distributions in phase space, namely the Q and Wigner functions, are studied in detail. We also propose two methods of generation of the negative binomial states.Comment: 17 pages, 5 figures, Accepted in EPJ

Leptophilic dark matter in gauged U(1)Le−LμU(1)_{L_e-L_\mu} model in light of DAMPE cosmic ray e++e−e^+ + e^- excess

Motivated by the very recent cosmic-ray electron+positron excess observed by DAMPE collaboration, we investigate a Dirac fermion dark matter (DM) in the gauged $L_e - L_\mu$ model. DM interacts with the electron and muon via the $U(1)_{e-\mu}$ gauge boson $Z^{'}$. The model can explain the DAMPE data well. Although a non-zero DM-nucleon cross section is only generated at one loop level and there is a partial cancellation between $Z^{'}ee$ and $Z^{'}\mu\mu$ couplings, we find that a large portion of $Z^{'}$ mass is ruled out from direct DM detection limit leaving the allowed $Z^{'}$ mass to be close to two times of the DM mass. Implications for $pp \to Z^{'} \to 2\ell$ and $pp \to 2\ell + Z^{'}$ , and muon $g-2$ anomaly are also studied.Comment: Discussions added, version accepted by EPJ

Vacuum stability in stau-neutralino coannihilation in MSSM

The stau-neutralino coannihilation provides a feasible way to accommodate the observed cosmological dark matter (DM) relic density in the minimal supersymmetric standard model (MSSM). In such a coannihilation mechanism the stau mass usually has an upper bound since its annihilation rate becomes small with the increase of DM mass. Inspired by this observation, we examine the upper limit of stau mass in the parameter space with a large mixing of staus. We find that the stau pair may dominantly annihilate into dibosons and hence the upper bound on the stau mass ($\sim400$ GeV) obtained from the $f\bar{f}$ final states can be relaxed. Imposing the DM relic density constraint and requiring a long lifetime of the present vacuum, we find that the lighter stau mass can be as heavy as about 1.4 TeV for the stau maximum mixing. However, if requiring the present vacuum to survive during the thermal history of the universe, this mass limit will reduce to about 0.9 TeV. We also discuss the complementarity of vacuum stability and direct detections in probing this stau coannihilation scenario.Comment: 12 pages, 6 figure

A minimal U(1)′U(1)^\prime extension of MSSM in light of the B decay anomaly

Motivated by the $R_K$ and $R_{K^*}$ anomalies from B decays, we extend the minimal supersymmetric model with a non-universal anomaly-free $U(1)^\prime$ gauge symmetry, coupling non-universally to the lepton sector as well as the quark sector. In particular, only the third generation quarks are charged under this $U(1)^\prime$, which can easily evade the dilepton bound from the LHC searches. An extra singlet is introduced to break this $U(1)^\prime$ symmetry allowing for the $\mu$-term to be generated dynamically. The relevant constraints of $B_s-\bar{B}_s$ mixing, $D^0-\bar{D}^0$ mixing and the LHC dilepton searches are considered. We find that in the allowed parameter space this $U(1)^\prime$ gauge interaction can accommodate the $R_K$ and $R_{K^*}$ anomalies and weaken considerably the $Z^\prime$ mass limits while remaining perturbative up to the Planck scale.Comment: 12 pages,2 figure

Probing GeV-scale MSSM neutralino dark matter in collider and direct detection experiments

Given the recent constraints from the dark matter (DM) direct detections, we examine a light GeV-scale (2-30 GeV) neutralino DM in the alignment limit of the Minimal Supersymmetric Standard Model (MSSM). In this limit without decoupling, the heavy CP-even scalar $H$ plays the role of the Standard Model (SM) Higgs boson while the other scalar $h$ can be rather light so that the DM can annihilate through the $h$ resonance or into a pair of $h$ to achieve the observed relic density. With the current collider and cosmological constraints, we find that such a light neutralino DM above 6 GeV can be excluded by the XENON-1T (2017) limits while the survivied parameter space below 6 GeV can be fully covered by the future germanium-based light dark matter detections (such as CDEX), by the Higgs coupling precison measurements or by the production process $e^+e^- \to hA$ at an electron-positron collider (Higgs factory).Comment: 15 pages, 5 figures. Discussions and references added, version accepted by PL

Localized Malignant Myxoid Anaplastic Mesothelioma of the Pericardium

Primary malignant mesothelioma of the pericardium is a rare cardiac neoplasm. Most are diffuse and have poor prognosis with median survival of six months. In the paper, we describe a young male patient having no exposure history of asbestos with localized malignant myxoid mesothelioma of the pericardium. The tumor displayed significant myxoid change in stroma, and anaplastic cytology, including pleomorphy, poor cohesion, prominent nuclei, with high mitoses, which led to difficulty in diagnosis. The tumor showed typical immunohistochemical phenotypes of mesothelioma, positive for WT-1, calretinin and CK5/6. Ki-67 labeling index was about 50% in general and nearly 80% in the most active areas. The patient showed better outcome. The report suggests the diagnosis of myxoid mesothelioma is supposed to rely on clinical data, and immunohistochemistry is assumed to be for differentiation

Simplified TeV leptophilic dark matter in light of DAMPE data

Using a simplified framework, we attempt to explain the recent DAMPE cosmic $e^+ + e^-$ flux excess by leptophilic Dirac fermion dark matter (LDM). The scalar ($\Phi_0$) and vector ($\Phi_1$) mediator fields connecting LDM and Standard Model particles are discussed. Under constraints of DM relic density, gamma-rays, cosmic-rays and Cosmic Microwave Background (CMB), we find that the couplings $P \otimes S$, $P \otimes P$, $V \otimes A$ and $V \otimes V$ can produce the right bump in $e^+ + e^-$ flux for a DM mass around 1.5 TeV with a natural thermal annihilation cross-section $\sim 3 \times 10^{-26} cm^3/s$ today. Among them, $V \otimes V$ coupling is tightly constrained by PandaX-II data (although LDM-nucleus scattering appears at one-loop level) and the surviving samples appear in the resonant region, $m_{\Phi_1} \simeq 2m_{\chi}$. We also study the related collider signatures, such as dilepton production $pp \to \Phi_1 \to \ell^+\ell^-$, and muon $g-2$ anomaly. Finally, we present a possible $U(1)_X$ realization for such leptophilic dark matter.Comment: discussions added, version accepted by JHE