Publications (151)416.68 Total impact
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ABSTRACT: The multisector SUSY breaking predicts pseudogoldstino which can couple to the visible sector more strongly than the ordinary gavitino and thus induce the decays of the lightest neutralino and chargino (collectively called electroweakinos) inside the detector. In this note we study the electroweakino pair productions via vector boson fusion (VBF) processes followed by decays to pseudogoldstino at the LHC. Our Monte Carlo simulations show that at the 14 TeV LHC with 3000 fb^{1} luminosity the dominant production channel pp>chargino+neutralino+2 jets can have a statistical significance above 2sigma while other production channels are not accessible.11/2014;  [Show abstract] [Hide abstract]
ABSTRACT: We explore the explanation of the Fermi Galactic Center Excess (GCE) in the NexttoMinimal Supersymmetric Standard Model. We systematically impose various experimental constraints and perform a fit to the updated Higgs data. For each surviving sample we further generate its gammaray spectrum from dark matter (DM) annihilation and compare it directly with the Fermi data. We find that the GCE can be explained by the annihilation $\chi \chi \to a^\ast \to b \bar{b}$ only when the CPodd scalar satisfies $m_a \simeq 2 m_\chi$, and in order to obtain the measured DM relic density, a sizable $Z$mediated contribution to DM annihilation must intervene in the early universe. As a result, the higgsino mass $\mu$ is upper bounded by about 350 GeV. Detailed Monte Carlo simulations on the $3\ell+ E_T^{miss}$ signal from neutralino/chargino associated production at 14TeV LHC indicate that the explanation can be mostly (completely) excluded at $95%$ C.L. with an integrated luminosity of 100(200) fb$^{1}$.10/2014;  [Show abstract] [Hide abstract]
ABSTRACT: Considering the constraints from collider experiments and dark matter detections, we investigate the SUSY effects in the Higgs productions $e^+e^ \to Zh$ at an $e^+e^$ collider with a centerofmass energy above 240 GeV and $\gamma\gamma \to h \to b\bar{b}$ at a photon collider with a centerofmass energy above 125 GeV. In the parameter space allowed by current experiments, we find that the SUSY corrections to $e^+e^ \to Zh$ can reach a few percent and the production rate of $\gamma\gamma \to h \to b\bar{b}$ can be enhanced by a factor of 1.2 over the SM prediction. We also calculate the exotic Higgs productions $e^+e^\to Zh_1$ and $e^+e^\rightarrow A_1h$ in the nexttominimal supersymmetric model (NMSSM) ($h$ is the SMlike Higgs, $h_1$ and $A_1$ are respectively the CPeven and CPodd singletdominant Higgs bosons which can be much lighter than $h$). We find that at a 250 GeV $e^+e^$ collider the production rates of $e^+e^\rightarrow Zh_1$ and $e^+e^\to A_1h$ can reach 60 fb and 0.1 fb, respectively.10/2014;  [Show abstract] [Hide abstract]
ABSTRACT: In some supersymmetric models like split supersymmetry or models with nonuniversal gaugino mass, bino (LSP) and winos (NLSP) may have rather small mass splitting in order to provide the correct dark matter relic density through bino/wino coannihilation. Such a scenario with the compressed bino/wino is difficult to explore at the LHC. In this work we propose to probe this scenario from $pp \to j \tilde{\chi}^0_2 \tilde{\chi}^\pm_1$ followed by $\tilde{\chi}^0_2 \to \gamma \tilde{\chi}^0_1$ and $\tilde{\chi}^\pm_1 \to W^{*}\tilde{\chi}^0_1\to \ell^\pm \nu \tilde{\chi}^0_1$ (this method is also applicable to the compressed bino/higgsino scenario). Through a detailed Monte Carlo simulation for both the signal and the backgrounds, we find that for a mass splitting $\Delta M \sim 515$ GeV between bino (LSP) and wino (NLSP), the 14 TeV LHC with luminosity of 500$fb^{1}$ can probe the wino up to 150 GeV (the sensitivity can reach $5\sigma$ for $\Delta M = 5$ GeV and $2\sigma$ for $\Delta M = 15$ GeV). We also investigate the dark matter detection sensitivities for this scenario and find that the planned XENON1T(2017) cannot fully cover the parameter space with wino below 150 GeV allowed by relic density and the LUX limits.09/2014;  [Show abstract] [Hide abstract]
ABSTRACT: We perform a detailed semianalytical analysis of the electroweak phase transition (EWPT) property in NMSSM, which serves as a good benchmark model in which the 126 GeV Higgs mixes with a singlet. In this case, a strongly first order electroweak phase transition (SFOEWPT) is achieved by the treelevel effects and the phase transition strength $\gamma_c$ is determined by the vacua energy gap at $T=0$. We make an anatomy of the energy gap at both treelevel and looplevel and extract out a dimensionless phase transition parameter $R_\kappa \equiv 4 \kappa v_s / A_\kappa$, which can replace $A_\kappa$ in the parameterization and affect the light CP odd and even Higgs spectra. We find that SFOEWPT only occurs in $R_\kappa \sim 1$ and positive $R_\kappa \lesssim \mathcal{O}(10)$, which in the nonPQ limit case would prefer either a relatively light CP odd or CP even Higgs boson $\sim (60, 100)$ GeV, therefore serves as a smoking gun signal and requires new search strategies at the LHC.05/2014;  [Show abstract] [Hide abstract]
ABSTRACT: In this work we show that the general singlet extension of the MSSM can naturally provide a selfinteracting singlino dark matter to solve the small cosmological scale anomalies (a large Sommerfeld enhancement factor can also be obtained). However, we find that the NMSSM (the singlet extension of the MSSM with Z3 symmetry) cannot achieve this due to the restricted parameter space. In our analysis we introduce the concept of symmetric and antisymmetric viscosity cross sections to deal with the nonrelativistic Majoranafermion dark matter scattering.04/2014;  [Show abstract] [Hide abstract]
ABSTRACT: In light of the Higgs discovery and the nonobservation of sparticles at the LHC, we revisit the SUSY induced top quark flavor changing decay into the Higgs boson. We perform a scan over the relevant parameter space of the MSSM by considering the constraints from the Higgs mass measurement, the LHC search for SUSY, the vacuum stability, the precision electroweak observables as well as $B \to X_s \gamma$. We obtain the following observations: (1) In the MSSM, the branching ratio of $ t \to c h$ can only reach $10^{6}$, which is about one order smaller than the old results before the LHC data. Among the considered constraints, the Higgs mass and the LHC sparticle search results are found to play an important role in limiting the prediction. (2) In the singlet extension of the MSSM, since the squark sector is less constrained by the Higgs mass, $Br(t \to c h)$ can reach $O(10^{5})$ in the allowed parameter space. (3) The chiralconserving mixings $\delta_{LL}$ and $\delta_{RR}$ have nondecoupling effects on $t \to c h$. Unlike the SUSYQCD correction to the $h\bar{b} b$ vertex, such nondecoupling effects are not sensitive to $\tan \beta$ and the CPodd Higgs boson mass $m_A$. For rather heavy squarks and gluino above $2 TeV$, $Br(t\to c h)$ can still reach $O(10^{7})$ under the constraints.04/2014;  [Show abstract] [Hide abstract]
ABSTRACT: The multisector SUSY breaking predicts the existence of goldstini, which could couple more strongly to visible fields than ordinary gravitino. Then the lightest neutralino and chargino can decay into a goldstini plus a Zboson, Higgs boson or Wboson. In this note we perform a Monte Carlo simulation for the direct productions of the lightest neutralino and chargino followed by the decays to goldstini. Considering scenarios with higgsinolike, binolike or winolike lightest neutralino, we find that the signaltobackground ratio at the high luminosity LHC is between 6 and 25% and the statistical significance can be above 5sigma.03/2014;  [Show abstract] [Hide abstract]
ABSTRACT: Motivated by the future precision test of the Higgs boson at an $e^+e^$ Higgs factory, we calculate the production $e^+e^ \to ZH\gamma$ in the Standard Model with complete nexttoleading order electroweak corrections. We find that for $\sqrt{s}=240$ (350) GeV the cross section of this production is sizably reduced by the electroweak corrections, which is $1.03$ (5.32) fb at leading order and 0.72 (4.79) fb at nexttoleading order. The transverse momentum distribution of the photon in the final states is also presented.11/2013;  [Show abstract] [Hide abstract]
ABSTRACT: In SUSY, a light dark matter is usually accompanied by light scalars to achieve the correct relic density, which opens new decay channels of the SM like Higgs boson. Under current experimental constraints including the latest LHC Higgs data and the dark matter relic density, we examine the status of a light neutralino dark matter in the framework of NMSSM and confront it with the direct detection results of CoGeNT, CDMSII and LUX. We have the following observations: (i) A dark matter as light as 8 GeV is still allowed and its scattering cross section off the nucleon can be large enough to explain the CoGeNT/CDMSII favored region; (ii) The LUX data can exclude a sizable part of the allowed parameter space, but still leaves a light dark matter viable; (iii) The SMlike Higgs boson can decay into the light dark matter pair with an invisible branching ratio reaching 30% under the current LHC Higgs data, which can be tested at the 14 TeV LHC experiment.Journal of High Energy Physics 11/2013; 2014(5). · 5.62 Impact Factor  [Show abstract] [Hide abstract]
ABSTRACT: We propose a new strategy to search for light, nearly degenerate higgsinos within the natural MSSM at LHC. We demonstrate that the entire higgsino mass range $\mu$ in 100200 GeV, which is preferred by the naturalness, can be probed at $5\sigma$ significance through the monojet search at 14 TeV HLLHC with 1500 fb$^{1}$ luminosity. The proposed method can also probe certain region in the parameter space for the lightest neutralino with a high higgsino purity, that cannot be reached by planned direct detection experiments at XENON1T(2017).Journal of High Energy Physics 10/2013; 2014(2). · 5.62 Impact Factor  [Show abstract] [Hide abstract]
ABSTRACT: We calculate the twoloop beta functions for three gauge couplings in split supersymmetry (splitSUSY) which assumes a very high scalar mass scale $M_S$. We find that in splitSUSY with a large $M_S$ the gauge coupling unification requires a lower bound on gaugino mass. Combined with the constraints from the dark matter relic density and direct detection limits, we find that splitSUSY is very restricted and the allowed parameter can be fully covered by XENON1T(2017). So the splitSUSY scenario with dark matter and gauge coupling unification requirements will be either discovered or excluded at XENON1T(2017).10/2013;  [Show abstract] [Hide abstract]
ABSTRACT: In the NexttoMinimal Supersymemtric Standard Model (NMSSM), one of the neutral Higgs scalars (CPeven or CPodd) may be lighter than half of the SMlike Higgs boson. In this case, the SMlike Higgs boson h can decay into such a light scalar pair and consequently the diphoton and ZZ signal rates at the LHC will be suppressed. In this work, we examine the constraints of the latest LHC Higgs data on such a possibility. We perform a comprehensive scan over the parameter space of the NMSSM by considering various experimental constraints and find that the LHC Higgs data can readily constrain the parameter space and the properties of the light scalar, e.g., at 3 sigma level this light scalar should be highly singlet dominant and the branching ratio of the SMlike Higgs boson decay into the scalar pair should be less than 30%. Also we investigate the detection of this scalar at various colliders. Through a detailed Monte Carlo simulation we find that under the constraints of the current Higgs data this light scalar can be accessible at the LHC14 with an integrated luminosity over 300 fb^{1}.09/2013;  [Show abstract] [Hide abstract]
ABSTRACT: Motivated by the recent progress of direct search for the productions of stop pair and sbottom pair at the LHC, we examine the constraints of the search results on the stop ($\tilde{t}_1$) mass in natural SUSY. We first scan the parameter space of natural SUSY in the framework of MSSM, considering the constraints from the Higgs mass, Bphysics and electroweak precision measurements. Then in the allowed parameter space we perform a Monte Carlo simulation for stop pair production followed by $\tilde{t}_{1} \to t \tilde{\chi}_{1}^{0}$ or $\tilde{t}_{1} \to b \tilde{\chi}_{1}^{+}$ and sbottom pair production followed by $\tilde{b}_{1} \to b \tilde{\chi}_{1}^{0}$ or $\tilde{b}_{1} \to t \tilde{\chi}_{1}^{}$. Using the combined results of ATLAS with 20.1 fb$^{1}$ from the search of $\ell+{\rm jets}+\slashed E_{T}$, hadronic $t\bar{t}+\slashed E_{T}$ and $2b+\slashed E_{T}$, we find that a stop lighter than 600 GeV can be excluded at 95% CL in this scenario.Journal of High Energy Physics 08/2013; 2013(10). · 5.62 Impact Factor 
Article: Dark matter in little Higgs model under current experimental constraints from LHC, Planck and Xenon
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ABSTRACT: We examine the status of dark matter (heavy photon) in the littlest Higgs model with Tparity (LHT) in light of the new results from the LHC Higgs search, the Planck dark matter relic density and the XENON100 limit on the dark matter scattering off the nucleon. We obtain the following observations: (i) For the LHC Higgs data, the LHT can well be consistent with the CMS results but disfavored by the ATLAS observation of diphoton enhancement; (ii) For the dark matter relic density, the heavy photon in the LHT can account for the Planck data for the small mass splitting of mirror lepton and heavy photon; (iii) For the dark matter scattering off the nucleon, the heavy photon can give a spinindependent cross section below the XENON100 upper limit for $m_{A_H}>95$ GeV ($f> 665$ GeV); (iv) A fit using the CMS Higgs data gives the lowest chisquare of 2.63 (the SM value is 4.75) at $f\simeq$ 1120 GeV and $m_{A_H}\simeq$ 170 GeV (at this point the dark matter constraints from Planck and XENON100 can also be satisfied). Such a best point and its nearby favored region (even for a $f$ value up to 3.8 TeV) can be covered by the future XENON1T (2017) experiment.Physical Review D 07/2013; 88(7). · 4.69 Impact Factor 
Article: Higgs pair production with SUSY QCD correction: revisited under current experimental constraints
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ABSTRACT: We consider the current experimental constraints on the parameter space of the MSSM and NMSSM. Then in the allowed parameter space we examine the Higgs pair production at the 14 TeV LHC via $b\bar{b}\to hh$ ($h$ is the 125 GeV SMlike Higg boson) with oneloop SUSY QCD correction and compare it with the production via $gg\to hh$. We obtain the following observations: (i) For the MSSM the production rate of $b\bar{b} \to hh$ can reach 50 fb and thus can be competitive with $gg \to hh$, while for the NMSSM $b\bar{b} \to hh$ has a much smaller rate than $gg \to hh$ due to the suppression of the $hb\bar{b}$ coupling by the singlet component of $h$; (ii) The SUSYQCD correction to $b\bar{b} \to hh$ is sizable, which can reach 30% for the MSSM and 10% for the NMSSM within the $1\sigma$ region of the Higgs data; (iii) In the heavy SUSY limit (all soft mass parameters become heavy), the SUSY effects decouple rather slowly from the Higgs pair production (especially the $gg\to hh$ process), which, for $M_{\rm SUSY}=5$ TeV and $m_A<1$ TeV, can enhance the production rate by a factor of 1.5 and 1.3 for the MSSM and NMSSM, respectively. So, the Higgs pair production at the LHC may be used to unravel the effects of heavy sparticles in case of nonobservation from direct search.07/2013; 
Article: Natural SUSY from SU(5) Orbifold GUT
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ABSTRACT: We propose a realistic 5D orbifold GUT model that can reduce to natural (or radiative natural) supersymmetry as the low energy effective theory. Supersymmetry as well as gauge symmetry are broken by the twist boundary conditions. We find that it is nontrivial to introduce other flavor symmetry other than the $SU(2)_R$ Rsymmetry. We ameliorate the tension between the small number of free parameters and the successful electroweak symmetry breaking by introducing nonminimal Kahler potentials. A large trilinear term $A_t$, which is necessary to give a 125 GeV Higgs boson, is naturally predicted in our scenario. A scan under current experimental constraints shows that our model can indeed realize natural (or radiative natural) supersymmetry.Journal of High Energy Physics 04/2013; · 5.62 Impact Factor  [Show abstract] [Hide abstract]
ABSTRACT: In order to have massive neutrinos, the righthanded neutrino/sneutrino superfield ($N$) need to be introduced in supersymmetry. In the framework of NMSSM (the MSSM with a singlet $S$) such an extension will dynamically lead to a TeVscale Majorana mass for the righthanded neutrino through the $SNN$ coupling when $S$ develops a vev (the free Majorana mass term is forbidden by the assumed $Z_3$ symmetry). Also, through the couplings $SNN$ and $SH_uH_d$, the SMlike Higgs boson (a mixture of $H_u$, $H_d$ and $S$) can naturally couple with the righthanded neutrino/sneutrino. As a result, the TeVscale righthanded neutrino/sneutrino may significantly contribute to the Higgs boson mass. Through an explicit calculation, we find that the Higgs boson mass can indeed be sizably altered by the righthanded neutrino/sneutrino. Such new contribution can help to push up the SMlike Higgs boson mass and thus make the NMSSM more natural.Journal of High Energy Physics 03/2013; 2013(7). · 5.62 Impact Factor 
Article: The SM extension with coloroctet scalars: diphoton enhancement and global fit of LHC Higgs data
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ABSTRACT: In light of the significant progress of the LHC to determine the properties of the Higgs boson, we investigate the capability of the ManoharWise model in explaining the Higgs data. This model extends the SM by one family of coloroctet and isospindoublet scalars, and it can sizably alter the coupling strengths of the Higgs boson with gluons and photons. We first examine the current constraints on the model, which are from unitarity, the LHC searches for the scalars and the electroweak precision data (EWPD).In implementing the unitarity constraint, we use the properties of the SU(3) group to simplify the calculation. Then in the allowed parameter space we perform a fit of the model, using the latest ATLAS and CMS data, respectively. We find that the ManoharWise model is able to explain the data with \chi^2 significantly smaller than the SM value. We also find that the current Higgs data, especially the ATLAS data, are very powerful in further constraining the parameter space of the model. In particular, in order to explain the diphoton enhancement reported by the ATLAS collaboration, the sign of the hgg coupling is usually opposite to that in the SM.Journal of High Energy Physics 03/2013; 2013(8). · 5.62 Impact Factor  [Show abstract] [Hide abstract]
ABSTRACT: We confront the little Higgs theory with the LHC Higgs search data (up to 17 fb$^{1}$ of the combined 7 and 8 TeV run). Considering some typical models, namely the littlest Higgs model (LH), the littlest Higgs model with Tparity (LHTA and LHTB) and the simplest little Higgs model (SLH), we scan over the parameter space in the region allowed by current experiments. We find that in these models the inclusive and exclusive (via gluongluon fusion) diphoton and $ZZ^*$ signal rates of the Higgs boson are always suppressed and approach to the SM predictions for a large scale $f$. Thus, the $ZZ^*$ signal rate is within the $1\sigma$ range of the experimental data while the inclusive diphoton signal rate is always outside the $2\sigma$ range. Especially, in the LHTA the diphoton signal rate is outside the $3\sigma$ range of the experimental data for $f < 800$ GeV. We also perform a global $\chi^2$ fit to the available LHC and Tevatron Higgs data, and find that these models provide no better global fit to the whole data set (only for some special channels a better fit can be obtained, specially in the LHTB).Physical review D: Particles and fields 03/2013; 87(5).
Publication Stats
2k  Citations  
416.68  Total Impact Points  
Top Journals
Institutions

1997–2014

Academia Sinica
Tâ€™aipei, Taipei, Taiwan


2009–2012

Chinese Academy of Sciences
 Institute of Theoretical Physics
Peping, Beijing, China 
Northeast Institute of Geography and Agroecology
 Institute of Theoretical Physics
Peping, Beijing, China


2002–2010

Yantai University
 Department of Physics
Beijing, Beijing Shi, China


2008–2009

Institute of physics china
Peping, Beijing, China


1992–2007

Henan Normal University
Henanâ€™an, Guangdong, China


2003

Hiroshima University
 Graduate School of Science
Hiroshimashi, Hiroshimaken, Japan


1998–2003

Tohoku University
 Department of Physics
Sendaishi, Miyagiken, Japan


1998–2001

Iowa State University
 Department of Physics and Astronomy
Ames, IA, United States


1996–1998

Northwestern University
 Department of Physics and Astronomy
Evanston, Illinois, United States
