Jin Min Yang

Academia Sinica, T’ai-pei, Taipei, Taiwan

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Publications (149)389.51 Total impact

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    ABSTRACT: We explore the explanation of the Fermi Galactic Center Excess (GCE) in the Next-to-Minimal 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 gamma-ray 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 CP-odd 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 14-TeV 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;
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    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 center-of-mass energy above 240 GeV and $\gamma\gamma \to h \to b\bar{b}$ at a photon collider with a center-of-mass 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 next-to-minimal supersymmetric model (NMSSM) ($h$ is the SM-like Higgs, $h_1$ and $A_1$ are respectively the CP-even and CP-odd singlet-dominant 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;
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    ABSTRACT: In some supersymmetric models like split supersymmetry or models with non-universal 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 co-annihilation. 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 $\Delta M \sim 5-15$ 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 XENON-1T(2017) cannot fully cover the parameter space with wino below 150 GeV allowed by relic density and the LUX limits.
    09/2014;
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    ABSTRACT: We perform a detailed semi-analytical 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 tree-level 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 tree-level and loop-level 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 non-PQ 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;
  • Fei Wang, Wenyu Wang, Jin Min Yang, Sihong Zhou
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    ABSTRACT: In this work we show that the general singlet extension of the MSSM can naturally provide a self-interacting 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 non-relativistic Majorana-fermion dark matter scattering.
    04/2014;
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    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 electro-weak 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 chiral-conserving mixings $\delta_{LL}$ and $\delta_{RR}$ have non-decoupling effects on $t \to c h$. Unlike the SUSY-QCD correction to the $h\bar{b} b$ vertex, such non-decoupling effects are not sensitive to $\tan \beta$ and the CP-odd 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;
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    Ken-ichi Hikasa, Tao Liu, Lin Wang, Jin Min Yang
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    ABSTRACT: The multi-sector 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 Z-boson, Higgs boson or W-boson. 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 higgsino-like, bino-like or wino-like lightest neutralino, we find that the signal-to-background ratio at the high luminosity LHC is between 6 and 25% and the statistical significance can be above 5-sigma.
    03/2014;
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    Ning Liu, Jie Ren, Lei Wu, Peiwen Wu, Jin Min Yang
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    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 next-to-leading 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 next-to-leading order. The transverse momentum distribution of the photon in the final states is also presented.
    11/2013;
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    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, CDMS-II 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/CDMS-II 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 SM-like 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.
    11/2013;
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    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 100-200 GeV, which is preferred by the naturalness, can be probed at $5\sigma$ significance through the monojet search at 14 TeV HL-LHC 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 XENON-1T(2017).
    10/2013;
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    Fei Wang, Wenyu Wang, Jin Min Yang
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    ABSTRACT: We calculate the two-loop beta functions for three gauge couplings in split supersymmetry (split-SUSY) which assumes a very high scalar mass scale $M_S$. We find that in split-SUSY 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 split-SUSY is very restricted and the allowed parameter can be fully covered by XENON-1T(2017). So the split-SUSY scenario with dark matter and gauge coupling unification requirements will be either discovered or excluded at XENON-1T(2017).
    10/2013;
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    ABSTRACT: In the Next-to-Minimal Supersymemtric Standard Model (NMSSM), one of the neutral Higgs scalars (CP-even or CP-odd) may be lighter than half of the SM-like Higgs boson. In this case, the SM-like 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 SM-like 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 LHC-14 with an integrated luminosity over 300 fb^{-1}.
    09/2013;
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    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, B-physics 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.
    08/2013;
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    Lei Wang, Jin Min Yang, Jingya Zhu
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    ABSTRACT: We examine the status of dark matter (heavy photon) in the littlest Higgs model with T-parity (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 spin-independent 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 chi-square 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
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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 SM-like Higg boson) with one-loop 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 SUSY-QCD 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 non-observation from direct search.
    07/2013;
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    Chengcheng Han, Fei Wang, Jin Min Yang
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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 non-trivial to introduce other flavor symmetry other than the $SU(2)_R$ R-symmetry. We ameliorate the tension between the small number of free parameters and the successful electroweak symmetry breaking by introducing non-minimal 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
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    Wenyu Wang, Jin Min Yang, Lin Lin You
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    ABSTRACT: In order to have massive neutrinos, the right-handed 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 TeV-scale Majorana mass for the right-handed 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 SM-like Higgs boson (a mixture of $H_u$, $H_d$ and $S$) can naturally couple with the right-handed neutrino/sneutrino. As a result, the TeV-scale right-handed 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 right-handed neutrino/sneutrino. Such new contribution can help to push up the SM-like Higgs boson mass and thus make the NMSSM more natural.
    Journal of High Energy Physics 03/2013; 2013(7). · 5.62 Impact Factor
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    Junjie Cao, Peihua Wan, Jin Min Yang, Jingya Zhu
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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 Manohar-Wise model in explaining the Higgs data. This model extends the SM by one family of color-octet and isospin-doublet 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 Manohar-Wise 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
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    ABSTRACT: In light of the recent LHC Higgs search data, we investigate the pair production of a SM-like Higgs boson around 125 GeV in the MSSM and NMSSM. We first scan the parameter space of each model by considering various experimental constraints, and then calculate the Higgs pair production rate in the allowed parameter space. We find that in most cases the dominant contribution to the Higgs pair production comes from the gluon fusion process and the production rate can be greatly enhanced, maximally 10 times larger than the SM prediction (even for a TeV-scale stop the production rate can still be enhanced by a factor of 1.3). We also calculate the chi-square value with the current Higgs data and find that in the most favored parameter region the production rate is enhanced by a factor of 1.45 in the MSSM, while in the NMSSM the production rate can be enhanced or suppressed (\sigma_{SUSY}/\sigma_{SM} varies from 0.7 to 2.4).
    Journal of High Energy Physics 01/2013; 2013(4). · 5.62 Impact Factor
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    Tao Liu, Lin Wang, Jin Min Yang
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    ABSTRACT: If supersymmetry is broken independently in multiple sectors with different scales, a number of goldstinos will be generated. One linear combination of these goldstinos is massless and eaten by the gravitino, while the orthogonal combinations acquire a tree level mass and become the physical states named goldstini (G'). Compared to the gravitino, such goldstini could couple more strongly to the visible fields and lead to some exotic phenomenology. In this note we first check the goldstini couplings in some GMSB models and find that the goldstini-photon-neutralino interaction may be very small while the goldstini-Z-neutralino and goldstini-Higgs-neutralino interactions may be sizable. This can induce a new decay mode for the Higgs boson: h-> G'+\chi -> Z+2G'. Then in an effective model with conservative fixed parameters we study the observability of this decay channel at the LHC and find that it is not accessible at the finished 8 TeV run (25 /fb) or 14 TeV run with 100 /fb, but might be observed at the high luminosity LHC (14 TeV, 1000-3000 /fb) if the systematics of the backgrounds can be well understood.
    Physics Letters B 01/2013; 726(1). · 4.57 Impact Factor

Publication Stats

2k Citations
389.51 Total Impact Points

Institutions

  • 1997–2014
    • Academia Sinica
      T’ai-pei, 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
      Henan’an, Guangdong, China
  • 2003
    • Hiroshima University
      • Graduate School of Science
      Hiroshima-shi, Hiroshima-ken, Japan
  • 1998–2003
    • Tohoku University
      • Department of Physics
      Sendai-shi, Miyagi-ken, 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