Motivated by the recent PAMELA and ATIC data, one is led to a scenario with heavy vector-like dark matter in association with a hidden $U(1)_X$ sector below GeV scale. Realizing this idea in the context of gauge mediated supersymmetry breaking (GMSB), a heavy scalar component charged under $U(1)_X$ is found to be a good dark matter candidate which can be searched for direct scattering mediated by the Higgs boson and/or by the hidden gauge boson. The latter turns out to put a stringent bound on the kinetic mixing parameter between $U(1)_X$ and $U(1)_Y$: $θ\lesssim 10^{-6}$. For the typical range of model parameters, we find that the decay rates of the ordinary lightest neutralino into hidden gauge boson/gaugino and photon/gravitino are comparable, and the former decay mode leaves displaced vertices of lepton pairs and missing energy with distinctive length scale larger than 20 cm for invariant lepton pair mass below 0.5 GeV. An unsatisfactory aspect of our model is that the Sommerfeld effect cannot raise the galactic dark matter annihilation by more than 60 times for the dark matter mass below TeV.
In order to achieve maximal stop mixing and m_h=125 GeV, we consider extensions of minimal GMSB that include marginal MSSM-messenger superpotential interactions. Using a new approach to analytic continuation in superspace, we derive general formulas for the soft masses in the presence of such interactions, correctly taking into account the role of MSSM-messenger mixing in a general framework for the first time. We classify and catalog all possible such interactions consistent with perturbative SU(5) unification, and we survey the impact of turning on one interaction at a time, from the point o…
A 125 GeV Higgs renders the simpler GMSB models unnatural, essentially pushing the soft spectrum beyond the LHC reach. A direct coupling of the matter and messenger fields, that facilitates an enhanced mixing in the squark sector, is a way to ameliorate this deficiency. We construct all possible messenger-matter interaction terms considering the messenger multiplets in 1, 5 and 10 dimensional representations of the SU(5). A Froggatt-Nielsen like flavor framework connected with the origin of fermion mass hierarchy is utilized to control the interaction terms and suppress FCNC. We perform a deta…
We present a gauge mediated supersymmetry breaking model having weak SU(2) triplet, color SU(3) octet and SU(5) 5-plet messengers, that can simultaneously explain the muon $(g-2)$ data within 1$σ$ and the observed Higgs boson mass of 125 GeV. Gauge coupling unification is nontrivially maintained. Most of the parameter space satisfying both is accessible to the 14 TeV LHC. The lighter of the two staus weighs around (100-200) GeV, which can be a potential target of the ILC.
We simulate precision measurements of gauge-mediated supersymmetry breaking (GMSB) parameters at a 500 GeV e+e- linear collider in the scenario where a neutralino is the next-to-lightest supersymmetric particle. Information on the supersymmetry breaking and the messenger sectors of the theory is extracted from the measured sparticle mass spectrum and neutralino lifetime.
We show that it is possible to introduce the confining hidden sector gauge group SU(5)' with the chiral matter 10 plus 5-bar, which are neutral under the standard model gauge group, toward a gauge mediated supersymmetry breaking (GMSB) in a Z_{12-I} orbifold compactification of E_8xE_8 heterotic string. Three families of MSSM result without exotics. We also find a desirable matter parity P (or R-parity) assignment. We note that this model contains the spectrum of the Lee-Weinberg model which has a nice solution of the mu problem.
Assuming gauge-mediated supersymmetry breaking, we simulate precision measurements of fundamental parameters at a 500 GeV e+e- linear collider in the scenario where a neutralino is the next-to-lightest supersymmetric particle. Information on the supersymmetry breaking and the messenger sectors of the theory is extracted from realistic fits to the measured mass spectrum of the Minimal Supersymmetric Model particles and the next-to-lightest supersymmetric particle lifetime.
Extensions of GMSB models were explored to explain the recent reports of the Higgs boson mass around 124-126 GeV. Some models predict a large mu term, which can spoil the vacuum stability of the universe. We study two GMSB extensions: i) the model with a large trilinear coupling of the top squark, and ii) that with extra vector-like matters. In both models, the vacuum stability condition provides upper bounds on the gluino mass if combined with the muon g-2. The whole parameter region is expected to be covered by LHC at sqrt{s} = 14 TeV. The analysis is also applied to the mSUGRA models with t…
Under the minimal SUSY standard model (MSSM), the discrepancy in the muon g-2 suggests the SUSY particles are of order 100 GeV, which is also supported by discussions on the little hierarchy problem. However, the LHC experiments have found no scalar-quarks or gluinos in such mass range, and moreover, the Higgs boson mass of 126 GeV requires, within the MSSM framework, the scalar-top mass of order 1-10 TeV. This current status forces us to abandon the simplest supersymmetry-breaking frameworks of the CMSSM and the GMSB scenarios. The V-MSSM is investigated in this dissertation, which is propose…
We investigate the effects of messenger-matter mixing on the lightest CP-even Higgs boson mass m_h in gauge-mediated supersymmetry breaking models. It is shown that with such mixings m_h can be raised to about 125 GeV, even when the superparticles have sub-TeV masses, and when the gravitino has a cosmologically preferred sub-keV mass. In minimal gauge mediation without messenger-matter mixing, realizing m_h = 125 GeV would require multi-TeV SUSY spectrum. The increase in $m_h$ due to messenger-matter mixing is maximal in the case of messengers belonging to 10+\bar{10} of SU(5) unification, whi…
The status of two on-going studies concerning important aspects of the phenomenology of gauge-mediated supersymmetry breaking (GMSB) models at TeV colliders is reported. The first study deals with the characteristics of the light Higgs boson spectrum allowed by the (minimal and non-minimal) GMSB framework. Today's most accurate GMSB model generation and two-loop Feynman-diagrammatic calculation of m_h have been combined. The Higgs masses are shown in dependence of various model parameters at the messenger and electroweak scales. In the minimal model, an upper limit on m_h of about 124 GeV is f…
Recently, both the ATLAS and CMS experiments have observed an excess of events that could be the first evidence for a 125 GeV Higgs boson. We investigate an implication of the CP-even Higgs boson with mass around 125 GeV in the context of the minimal gauge mediated supersymmetry breaking (mGMSB). In mGMSB, gravitino is the lightest sparticle (LSP) and hence the dark matter candidate. We consider the so-called superWIMP scenario where the dark matter gravitino is non-thermally produced by the decay of the next-to-LSP (NLSP) bino-like neutralino after its freeze-out. For a given $\tan β$ and the…
Gauge mediation model with vectorlike matters (V-GMSB) is one of the few viable SUSY models that explains the 126 GeV Higgs boson mass and the muon anomalous magnetic moment simultaneously. We explore exclusion bounds on V-GMSB model from latest LHC SUSY searches.
We explored the sparticle mass spectrum in light of the muon g-2 anomaly and the little hierarchy problem in a class of gauge mediated supersymmetry breaking model. Here the messenger fields transform in the adjoint representation of the Standard Model gauge symmetry. To avoid unacceptably light right-handed slepton masses the standard model is supplemented by additional U(1)_B-L gauge symmetry. Considering a non-zero U(1)_B-L D-term leads to an additional contribution to the soft supersymmetry breaking mass terms which makes the right-handed slepton masses compatible with the current experime…
We propose to accommodate economically the type-II neutrino seesaw mechanism in (G)NMSSM from GMSB and AMSB, respectively. The heavy triplets within neutrino seesaw mechanism are identified to be the messengers. Therefore, the $μ$-problem, the neutrino mass generation, LFV as well the soft SUSY breaking parameters can be economically combined in a non-trivial way. General features of such extensions are discussed. The type-II neutrino seesaw-specific interactions can give additional Yukawa deflection contributions to the soft SUSY breaking parameters of NMSSM, which are indispensable to realiz…
We consider the phenomenology of a class of gauge-mediated supersymmetry (SUSY) breaking (GMSB) models at a e+e- Linear Collider (LC) with c.o.m. energy up to 500 GeV. In particular, we refer to a high-luminosity (L ~ 3 x 10^34 cm^-2 s^-1) machine, and use detailed simulation tools for a proposed detector. Among the GMSB-model building options, we define a simple framework and outline its predictions at the LC, under the assumption that no SUSY signal is detected at LEP or Tevatron. Our focus is on the case where a neutralino (N1) is the next-to-lightest SUSY particle (NLSP), for which we dete…
The production and the final abundance of gravitino dark matter appear to depend crucially on the restoration of the global U(1) $R$-symmetry of GMSB sectors in a threefold way. An $R$-symmetric phase effectively suppresses the production of goldstinos from scatterings with the supersymmetric Standard Model particles and it generically initiates the goldstino production from the thermalized messenger particles. In addition, the GMSB spurion gets displaced from the zero temperature minimum and under certain conditions it dominates the energy density of the universe producing late entropy. We sh…
The ATLAS and CMS collaborations recently reported indication of a Higgs boson around 125 GeV. If we add extra vector-like quarks to the MSSM, such a relatively heavy Higgs can be naturally realized in the GMSB framework, simultaneously explaining the muon g-2 anomaly. I will discuss LHC prospects of this attractive model.
We study the muon anomalous magnetic moment (muon g-2) and the Higgs boson mass in a simple extension of the minimal supersymmetric (SUSY) Standard Model with extra vector-like matters, in the frameworks of gauge mediated SUSY breaking (GMSB) models and gravity mediation (mSUGRA) models. It is shown that the deviation of the muon g-2 and a relatively heavy Higgs boson can be simultaneously explained in large tan-beta region. (i) In GMSB models, the Higgs mass can be more than 135 GeV (130 GeV) in the region where muon g-2 is consistent with the experimental value at the 2 sigma (1 sigma) level…
Recent indications of a 125 GeV Higgs boson are challenging for gauge-mediated supersymmetry breaking (GMSB), since radiative contributions to the Higgs boson mass are not enhanced by significant stop mixing. This challenge should not be considered in isolation, however, as GMSB also generically suffers from two other problems: unsuppressed electric dipole moments and the absence of an attractive dark matter candidate. We show that all of these problems may be simultaneously solved by considering heavy superpartners, without extra fields or modified cosmology. Multi-TeV sfermions suppress the …
We study phenomenological aspects of the MSSM with extra U(1) gauge symmetry. We find that the lightest Higgs boson mass can be increased up to 125 GeV, without introducing a large SUSY scale or large A-terms, in the frameworks of the CMSSM and gauge mediated SUSY breaking (GMSB) models. This scenario can simultaneously explain the discrepancy of the muon anomalous magnetic moment (muon g-2) at the 1 sigma level, in both of the frameworks, U(1)-extended CMSSM/GMSB models. In the CMSSM case, the dark matter abundance can also be explained.
The sweet spot supersymmetry (SUSY) solves the mu problem in the Minimal Supersymmetric Standard Model (MSSM) with gauge mediated SUSY breaking (GMSB) via the generalized Giudice-Masiero (GM) mechanism where only the mu-term and soft Higgs masses are generated at the unification scale of the Grand Unified Theory (GUT) due to the approximate PQ symmetry. Because all the other SUSY breaking soft terms are generated via the GMSB below the GUT scale, there exists SUSY electroweak (EW) fine-tuning problem to explain the 125 GeV Higgs boson mass due to small trilinear soft term. Thus, to explain the…
The discovery of a 125.5 GeV Higgs with standard model-like couplings and naturalness considerations motivate gauge extensions of the MSSM. We analyse two variants of such an extension and carry out a phenomenological study of regions of the parameter space satisfying current direct and indirect constraints, employing state-of-the art two-loop RGE evolution and GMSB boundary conditions. We find that due to the appearance of non-decoupled D-terms it is possible to obtain a 125.5 GeV Higgs with stops below 2 TeV, while the uncolored sparticles could still lie within reach of the LHC. We compare …
The SUSY contributions $Δa_μ$ to muon $g-2$ anomaly can not even reach $3σ$ in ordinary gauge mediated SUSY breaking (GMSB) scenarios because of the strong correlations between the colored sparticle masses and the uncolored EW sparticle masses. An interesting extension to GMSB is the (Extra)Ordinary Gauge Mediation (EOGM), which can relax the correlations between squarks and sleptons with non-universal choices for $N_{eff,3}$ and $N_{eff,2}$. We find that EOGM scenarios with $N_{eff,3}\ll N_{eff,2}$ can explain the muon $g-2$ anomaly within $3σ$ range, however can not explain the new W-boson m…
The $Bμ/μ$ solution in GMSB via the hidden sector dynamics is simple and natural. However, it has some obstacles to be physical. To circumvent this situation, we introduce the visible and the hidden branes, each of which has its own U(1) symmetry, in a five dimensional setup. In the bulk we allow Chern-Simons coupling between the visible and the hidden U(1)s which gives an enhancement of the mass of bino. If this gives a considerable contribution to the mass of bino, we can get a proper radiative electro weak symmetry breaking with the boundary conditions, in which $Bμ$ and squared scalar mass…
To obtain a SM-like Higgs boson around 125 GeV in the Minimal Supersymmetric Standard Model with minimal gauge mediation of supersymmetry breaking (GMSB), a heavy stop at multi-TeV level is needed and incurs severe fine-tuning, which can be ameliorated in the framework of the deformed GMSB with visible-hidden direct Yukawa interactions (YGMSB). We examine some general features of the YGMSB and focus on the scenario with Higgs-messenger couplings (H-YGMSB) which can automatically maintain the minimal flavor violation (MFV). It turns out that such a Yukawa mediation scenario can give a large -A_…
It is shown that gravitinos with mass m_{3/2} ~ 0.1-1 MeV may provide suitable cold dark matter candidates in scenarios of gauge mediated supersymmetry breaking (GMSB) under SO(10) grand unification coupled to supergravity, which accommodate a messenger sector of mass scale M_X ~ 10^6 GeV. This is due to the combined effects of renormalizable loop-suppressed operators and generic non-renormalizable ones governing the dilution of a pre-existing equilibrium gravitino abundance via messenger decay. The above range of gravitino and messenger masses can be accommodated in indirect GMSB scenarios. T…
We study the conditions for successful Affleck-Dine baryogenesis and the origin of gravitino dark matter in GMSB models. AD baryogenesis in GMSB models is ruled out by neutron star stability unless Q-balls are unstable and decay before nucleosynthesis. Unstable Q-balls can form if the messenger mass scale is larger than the flat-direction field Phi when the condensate fragments. We provide an example based on AD baryogenesis along a d = 6 flat direction for the case where m_{3/2} \approx 2 GeV, as predicted by gravitino dark matter from Q-ball decay. Using a phenomenological GMSB potential whi…
We discuss mechanisms for naturally generating GeV-scale hidden sectors in the context of weak-scale supersymmetry. Such low mass scales can arise when hidden sectors are more weakly coupled to supersymmetry breaking than the visible sector, as happens when supersymmetry breaking is communicated to the visible sector by gauge interactions under which the hidden sector is uncharged, or if the hidden sector is sequestered from gravity-mediated supersymmetry breaking. We study these mechanisms in detail in the context of gauge and gaugino mediation, and present specific models of Abelian GeV-scal…
Hidden sector particles with sub-GeV masses like hidden U(1) gauge bosons, the NMSSM CP-odd Higgs, and other axion-like particles are experimentally little constrained as they interact only very weakly with the visible sector. For masses below the muon threshold, we present constraints from meson decays, g - 2 as well as beam-dump and reactor experiments. The NMSSM CP-odd Higgs and generally any pseudoscalar is required to be heavier than 210 MeV or couple to fermions much weaker than the SM Higgs. Hidden photons are less constrained and can be searched for at future fixed-target experiments, …
The lighter neutral scalar Higgs mass is examined in gauge-mediated supersymmetry-breaking models in which the messenger sector responsible for SUSY breaking is allowed to involve more general sets of $SU(3) \otimes SU(2) \otimes U(1)$ multiplets than those contained in the SU(5) $5 + \bar{5}$ or $10 + \bar{10}$ multiplets. The largest mass for the lighter scalar Higgs is found to be 132 GeV when the breaking parameter $Λ$ is taken to be 100 TeV\@. Thus the predictions for the lightest Higgs mass can be tested at the upgraded Tevatron runs for these general classes of GMSB models.
We explore quark interactions mediated by new gauge bosons of masses in the 0.3 - 50 GeV range. A tight upper limit on the gauge coupling of light Z' bosons is imposed by the anomaly cancellation conditions in conjunction with collider bounds on new charged fermions. Limits from quarkonium decays are model dependent, while electroweak constraints are mild. We derive the limits for a Z' boson coupled to baryon number, and then construct a Z' model with relaxed constraints, allowing quark couplings as large as 0.2 for a mass of a few GeV.
In order to significantly raise the mass of the supersymmetry Higgs boson, we consider a radiative correction to it by heavy (\sim 1 TeV) hidden sector fields, which communicate with the Higgs through relatively heavy "messengers" (300-500 GeV). The messenger fields (S, \bar{S}) are coupled to the Higgs ("y_HSH_uH_d," y_H\lesssim 0.7) and also to hidden sector fields with a Yukawa coupling of order unity. The hidden sector fields are assumed to be large representations of a hidden gauge group, and so their scalar partner masses can be heavier than other typical soft scalars in the visible sect…
We explain the recent diphoton excesses around $750$ GeV by both ATLAS and CMS as a singlet scalar $Φ$ which couples to SM gluon and neutral gauge bosons only through higher dimensional operators. A natural explanation is that $Φ$ is a pseudo-Nambu-Goldstone boson (pNGB) which receives parity violation through anomaly if there exists a hidden strong dynamics. The singlet and other light pNGBs will decay into two SM gauge bosons and even serves as the meta-stable coloured states which can be probed in the future. By accurately measuring their relative decay and the total production rate in the …
In this paper, we investigate the spectra of the prospective hidden-bottom and -charm hexaquark states with quantum numbers $J^{PC }= 0^{++}$, $0^{-+}$, $1^{++}$ and $1^{--}$ in the framework of QCD sum rules. By constructing appropriate interpreting currents, the QCD sum rules analyses are performed up to dimension 12 of the condensates. Results indicate that there exist two possible baryonium states in $b$-quark sector with masses $11.84 \pm 0.22$ GeV and $11.72 \pm 0.26$ GeV for $0^{++}$ and $1^{--}$, respectively. The corresponding hidden-charm partners are found lying respectively at $5.1…
The masses of cryptoexotic pentaquarks with hidden beauty are estimated phenomenologically using the results by the LHCb collaboration which discovered recently the cryptoexotic pentaquarks with hidden charm. The expected masses of the hidden beauty pentaquarks are about $10.8$ GeV and $10.7$ GeV in the limit of some kind of heavy quark symmetry. The states with hidden strangeness considered in similar way have masses about $2.37$ Gev and $2.30$ GeV, by several hundreds of MeV higher than states discussed previously in connection with the relatively light positive strangeness pentaquark $θ^+$.…
Asymmetric Dark Matter (ADM) models relate the dark matter density to the baryon asymmetry, so that a natural mass scale for ADM is around a few GeV. In existing models of ADM, this mass scale is unexplained; here we generate this GeV scale for dark matter (DM) from the weak scale via gauge kinetic mixing with a new Abelian dark force. In addition, this dark sector provides an efficient mechanism for suppressing the symmetric abundance of DM through annihilations to the dark photon. We augment this sector with a higher dimensional operator responsible for communicating the baryon asymmetry to …
In this short note, we revisit the model of a CP-even singlet scalar resonance proposed in arXiv:1507.02483, where the resonance appears as the lightest composite state made of scalar quarks participating in hidden strong dynamics. We show that the model can consistently explain the excess of diphoton events with an invariant mass around 750GeV reported by both the ATLAS and CMS experiments. We also discuss the nature of the charged composite states in the TeV range which accompany to the neutral scalar. Due to inseparability of the dynamical scale and the mass of the resonance, the model also…
The interactions of $\bar{D}Σ_{c}$-$\bar DΛ_c$, $\bar{D}^{*}Σ_{c}$-$\bar D^*Λ_c$, and related strangeness channels, are studied within the framework of the coupled channel unitary approach with the local hidden gauge formalism. A series of meson-baryon dynamically generated relatively narrow $N^*$ and $Λ^*$ resonances are predicted around 4.3 GeV in the hidden charm sector. We make estimates of production cross sections of these predicted resonances in $\bar{p} p $ collisions for PANDA at the forthcoming FAIR facility.
A dynamical calculation of the strange hidden charm pentaquark systems $Λ_{c\bar{c}}$ is performed in the framework of the quark delocalization color screening model. The effective potentials between two clusters are calculated to investigate the interaction between the baryons and mesons. The dynamic calculations indicate that the strange hidden charm pentaquark system with $IJ^{P}=0\frac{1}{2}^{-}$ and $IJ^{P}=0\frac{3}{2}^{-}$ can form bound states with the help of the channel-coupling. The energies of these two system are 4094.3 MeV and 4207.4 Mev, respectively. These two $Λ_{c\bar{c}}$ st…
Recent results from the experimental collaborations at LHC give hints of a resonance in the diphoton channel at an invariant mass of 750 GeV. We show that such a scalar resonance would be possible in an $U(1)$ extension of the SM where the extended symmetry is hidden and yet to be discovered. We explore the possibilities of accommodating this excess by introducing a minimal extension to the matter content and highlight the parameter space that can accommodate the observed diphoton resonance in the model. The model also predicts new interesting signals that may be observed at the current LHC ru…
We present a particle physics model to explain the observed enhancement in the Xenon-1T data at an electron recoil energy of 2.5 keV. The model is based on a $U(1)$ extension of the Standard Model where the dark sector consists of two essentially mass degenerate Dirac fermions in the sub-GeV region with a small mass splitting interacting with a dark photon. The dark photon is unstable and decays before the big bang nucleosynthesis, which leads to the dark matter constituted of two essentially mass degenerate Dirac fermions. The Xenon-1T excess is computed via the inelastic exothermic scatterin…
In this work, we investigate the interactions between the charmed-strange meson ($D_s, D_s^{*}$) in $H$-doublet and the (anti-)charmed-strange meson ($D_{s1}, D_{s2}^{*}$) in $T$-doublet, where the one boson exchange model is adopted by considering the $S$-$D$ wave mixing and the coupled-channel effects. By extracting the effective potentials for the discussed $H_s\bar{T}_s$ and $H_s{T}_s$ systems, we try to find the bound state solutions for the corresponding systems. We predict the possible hidden-charm hadronic molecular states with hidden strangeness, i.e., the $D_s^{*}\bar D_{s1}+c.c.$ st…
We study the mass spectra of hidden-charm pentaquarks having spin $J = {1\over2}/{3\over2}/{5\over2}$ and quark contents $uud c \bar c$. We systematically construct all the relevant local hidden-charm pentaquark currents, and select some of them to perform QCD sum rule analyses. We find that the $P_c(4380)$ and $P_c(4450)$ can be identified as hidden-charm pentaquark states composed of an anti-charmed meson and a charmed baryon. Besides them, we also find a) the lowest-lying hidden-charm pentaquark state of $J^P = 1/2^-$ has the mass $4.33^{+0.17}_{-0.13}$ GeV, while the one of $J^P = 1/2^+$ i…
We discuss new physics phenomenology of hidden scalar ($S$), pseudoscalar ($P$), vector ($V$) and axial-vector ($A$) particles coupled to nucleons and leptons, which could give contributions to proton charge radius, $(g-2)_μ$, $^8$Be-$^4$He anomaly and electric dipole moment (EDM) of Standard Model (SM) particles. In particular, we estimate sensitivity of NA64$μ$ experiment to observe muon missing energy events involving hidden scalar and vector particles. That analysis is based on {\tt GEANT4} Monte Carlo simulation of the signal process of muon scattering off target nuclei $μN \to μN S(V)$ f…
We study a simple model in which the recently reported 750 GeV diphoton excess arises from a composite pseudo Nambu-Goldstone boson---hidden pion---produced by gluon fusion and decaying into two photons. The model only introduces an extra hidden gauge group at the TeV scale with a vectorlike quark in the bifundamental representation of the hidden and standard model gauge groups. We calculate the masses of all the hidden pions and analyze their experimental signatures and constraints. We find that two colored hidden pions must be near the current experimental limits, and hence are probed in the…
Motivated by the di-photon resonance recently reported by the ATLAS and CMS collaborations at $\sqrt{s} =13$ TeV, we interpret the resonance as a scalar boson $X (750)$ in hidden-valley-like models. The scalar boson $X$ can mix with the standard model Higgs boson and thus can be produced via gluon fusion. It then decays into a pair of very light hidden particles $Y$ of sub-GeV, each of which in turn decays to a pair of collimated $ π^{0} $'s, and these two $ π^{0} $'s decay into photons which then form photon-jets. A photon-jet ($ γ$-jet) is a special feature that consists of a cluster of coll…
We suggest a dark matter scenario which could contribute the possible anomaly observed by Fermi-LAT $γ$-ray space telescope. It is based on the model recently proposed by Weinberg. In our scenario the gamma-ray line signal comes from the fermionic dark matter ($M_{\rm DM}=214 $ GeV) annihilating into two light scalars with mass around 500 MeV which in turn decay into two neutral pions. Finally the pions can decay into two 130 GeV photons. The strong constraint from the direct detection leaves only the channel of the dark matter annihilation into two light scalars for both the relic density and…
Based on the generalized hidden local symmetry as the chiral model of pseudoscalar, vector, and axial vector mesons, the excitation curve of the reaction e^+e^-\toπ^+π^-π^+π^- is calculated for energies in the interval 0.65\leq \sqrt{s}\leq1 GeV. The theoretical predictions are compared to available data of CMD-2 and BaBaR. It is shown that the inclusion of heavy isovector resonances ρ(1450) and ρ(1700) is necessary for reconciling calculations with the data. It is found that at \sqrt{s}\approx1 GeV the contributions of the above resonances are much larger, by the factor of 30, than the ρ(770)…
We present a detailed study of the non-abelian vector dark matter candidate $W^\prime$ with a MeV-GeV low mass range, accompanied by a dark photon $A^\prime$ and a dark $Z^\prime$ of similar masses, in the context of a gauged two-Higgs-doublet model with the hidden gauge group that has the same structure as the Standard Model electroweak gauge group. The stability of dark matter is protected by an accidental discrete $Z_2$ symmetry ($h$-parity) which was usually imposed ad hoc by hand. We examine the model by taking into account various experimental constraints including dark photon searches a…
Recently, the XENON1T experiment has reported an excess in the electronic recoil events. The excess is consistent with the interpretation of absorption of 3keV bosonic dark matter, for example, hidden photon dark matter with kinetic mixing of the order of $10^{-15}$. We point out that the minimally gravitational production provides a viable mechanism for obtaining a correct relic hidden photon abundance. We present parameter dependence of the hidden photon dark matter abundance on the inflationary scale $H_{\rm inf}$ and also the reheating temperature $T_{\rm R}$. We show that the inflationary…
In light of the recent observation of the Fermi-LAT 130 GeV gamma-ray line, we suggest a model of scalar dark matter in hidden sector, which can decay into two (hidden) photons. The process is radiatively induced by a GUT scale fermion in the loop, which is charged under a hidden sector U(1), and the kinetic mixing ($\sim εF^{μν}F'_{μν}$) enables us to fit the required decay width for the Fermi-LAT peak. The model does not allow any dangerous decay channels into light standard model particles.
The existence of dark sectors, consisting of weakly-coupled particles that do not interact with the known Standard Model forces, is theoretically and phenomenologically motivated. The hidden particles are candidates for Dark Matter and can interact with photon through electric dipole moment (EDM) and magnetic dipole moment (MDM). We investigate the possibility a hidden sector's Dark Matter which is charged under a hidden $U(1)_X$ gauge symmetry can interact with photon at loop level. We evaluate the scattering cross section of hidden Dirac fermion with nuclei and set bounds for dipole moment. …
We show that the $2.4σ$ signal of the leptonic flavor violating (LFV) Higgs boson decay $h\toμτ$, as observed by the CMS collaboration recently, can be explained by a certain class of two-Higgs doublet models that allow controllable flavor-changing neutral current with minimal number of free parameters. We postulate that (i) the alignment limit is maintained, which means the lightest neutral scalar ($h$) has identical couplings to that of the Standard Model Higgs boson and (ii) the signal comes from two other neutral scalars, the CP-even $H$ and the CP-odd $A$, almost degenerate with $h$ at 12…
Calculations of deep inelastic processes (DIS) to next-to-next to leading order are discussed. Fitting $ep$ experiment in the range $2.5\leq Q^2\leq 230 GeV^2$, we find the coupling $α_s(M_Z^2)=0.1163\pm0.0023$. We also get the gluon density $xG(x,Q^2\simeq 10 GeV^2)=0.51 x^{-0.44}(1-x)^{8.1}$, and negative evidence for the existence of light gluinos
Our contribution sets out to investigate the GeV-scale phenomenology of a model based on an $SU_{L}(2) \times U_{Y}(1) \times U(1)_{X}$-gauge symmetry. The model accommodates, as a consequence of the symmetry-breaking pattern, a light gauge boson at the GeV-scale or below, allowing then to set up a new low energy physics. The fermion sector includes an exotic candidate to Dark Matter (DM) and the whole fermionic field content yields, as it is mandatory, the cancellation of the chiral anomaly. %In this strict sense, we refer to our proposal as a unified description : two different and exclusive…
