arXiv subjects

Sibo Zheng

Publications and source records attributed to Sibo Zheng.

At least 37 records · Page 2Linked to original sources

arXiv2021

Resolving XENON Excess With Decaying Cold Dark Matter

We propose a decaying cold dark matter model to explain the excess of electron recoil observed at the XENON1T experiment. In this scenario, the daughter dark matter from the parent dark matter decay easily obtains velocity large enough to saturate the peak of the electron recoil energy around 2.5 keV, and the observed signal rate can be fulfilled by the parent dark matter with a mass of order 10-200 MeV and a lifetime larger than the age of Universe. We verify that this model is consistent with experimental limits from dark matter detections, Cosmic Microwave Background and Large Scale Structure experiments.

hep-ph↗

arXiv2020

Probing Electroweak Dark Matter at 14 TeV LHC

Well-motivated electroweak dark matter is often hosted by an extended electroweak sector which also contains new lepton pairs with masses near the weak scale. In this paper, we explore such electroweak dark matter via combining dark matter direct detections and high-luminosity LHC probes of new lepton pairs. Using $Z$- and $W$-associated electroweak processes with two or three lepton final states, we show that dependent on the overall coupling constant, dark matter mass up to $170-210$ GeV can be excluded at $2σ$ level and up to $175-205$ GeV can be discovered at $5σ$ level at the 14 TeV LHC with integrated luminosities 300 fb$^{-1}$ and 3000 fb$^{-1}$, respectively.

hep-ph↗

arXiv2020

Probing Unification With Precision Higgs Physics

We propose a novel approach of probing grand unification through precise measurements on the Higgs Yukawa couplings at the LHC. This idea is well motivated by the appearance of effective operators not suppressed by the mass scale of unification $M_{\rm{U}}$ in realistic models of unification with the minimal structure of Yukawa sector. Such operators modify the Higgs Yukawa couplings in correlated patterns at scale $M_{\rm{U}}$ that hold up to higher-order corrections. The coherences reveal a feature that, the deviation of tau Yukawa coupling relative to its standard model value at the weak scale is the largest one among the third-generation Yukawa couplings. This feature, if verified by the future LHC, can serve as a hint of unification.

hep-ph↗

arXiv2020

Minimal Vectorlike Model in Supersymmetric Unification

Compared to the minimal supersymmetric standard model, an extension by vectorlike fermions is able to explain the Higgs mass while retains the grand unification. We investigate the minimal vectorlike model by focusing on the vectorlike electroweak sector. We firstly derive the mass spectrum in the electroweak sector, then calculate the one-loop effects on the Higgs physics, and finally explore either vectorlike or neutralino dark matter. Collider constraints are briefly discussed.

hep-ph↗

arXiv2019

Towards Realistic SUSY Grand Unification for Extended MSSM

Low-energy supersymmetric models such as MSSM, NMSSM and MSSM with vectorlike fermion are consistent with perturbative unification. While the non-minimal extensions naturally explain Higgs mass and dark matter in the low energy region, it is unclear how seriously they are constrained in the ultraviolet region. Our study shows that $i)$, In the case of embedding MSSM into $\rm{SU}(5)$, the fit to SM fermion masses requires a singlet $S$, which leads to unviable embedding of NMSSM into $\rm{SU}(5)$ because such $S$ feeds singlet $N$ a mass of order unification scale as well. $ii)$, Similar result holds in the case of embedding NMSSM into $\rm{SO}(10)$, where $S$ is replaced by some Higgs fields responsible for $\rm{SO}(10)$ breaking. $iii)$, On the contrary, for the embedding of MSSM with $16$-dimensional vectorlike fermions into $\rm{SO}(10)$, the Higgs field responsible for the vectorlike mass of order TeV scale can evade those problems the singlet $N$ encounters because of an intermediate mass scale in the $126$-dimensional Higgs field.

hep-ph↗

arXiv2019

Correlated Electric and Magnetic Dipole Moment in Natural Supersymmetry

In the context of supersymmetry, the two-loop Barr-Zee diagrams which induce CP-violating electric dipole moment of electron due to superpartners simultaneously yield CP-conserving magnetic dipole moment of muon. In this paper, we derive the coherence between the electric and magnetic dipole moments at two-loop level due to stops, charginos or neutralinos-charginos. We also use the coherence to constrain superpartner masses and their CP-violating phases, in the light of recent ACME limit on the electric dipole moment of electron and future experiments about magnetic dipole moment of muon such as Fermilab E989 experiment.

hep-ph↗

arXiv2019

Effective Field Theory of Majorana Dark Matter

We revisit thermal Majorana dark matter from the viewpoint of minimal effective field theory. In this framework, analytic results for dark matter annihilation into standard model particles are derived. The dark matter parameter space subject to the latest LUX, PandaX-II and Xenon-1T limits is presented in a model-independent way. Applications to singlet-doublet and MSSM are presented.

hep-ph↗

arXiv2018

Extended MSSM in Supersymmetric $\rm{SO}(10)$ Grand Unification

We apply the perturbative grand unification due to renormalization to distinguish TeV-scale relics of supersymmetric $\rm{SO}(10)$ scenarios. With rational theoretical constraints taken into account, we find that for the breaking pattern of either $\rm{SU}(5)$ or Pati-Salam only extra matter $\mathbf{16}$ supermultiplet of $SO(10)$ can appear at TeV scale, apart from MSSM spectrum.

hep-ph↗

arXiv2018

A Heavy Scalar at the LHC from Vector Boson Fusion

A hypothetical scalar mixed with the standard model Higgs appears in few contexts of new physics. This study addresses the question what mass range is in the reach of $14$ TeV LHC given different magnitudes of mixing angle $α$, where event simulations are based on production from vector boson fusion channel and decays into SM leptons through ${\rm WW}$ or ${\rm ZZ}$. It indicates that heavy scalar mass up to $539$ GeV and $937$ GeV can be excluded by integrated luminosity of $300$ $\rm{fb}^{-1}$ and $3000$ $\rm{fb}^{-1}$ respectively for $\sin^{2}α$ larger than $0.04$.

hep-ph↗

arXiv2018

Light Neutralino Dark Matter in the NMSSM

The next-to-minimal supersymmetric standard model can host light neutralino dark matter with mass of order GeV scale. It is dominated by the singlino component as a result of approximate Peccei-Quinn symmetry. This paper is devoted to address the question how light such neutralino dark matter can be in the light of the LHC Run 1 data as well as the latest LUX and Xenon1T limits. In particular, we show the sensitivity of parameter space of dark matter mass with respect to $Z$ boson and SM Higgs invisible decay.

hep-ph↗

arXiv2017

Effective Higgs Theories in Supersymmetric Grand Unification

The effective Higgs theories at the TeV scale in supersymmetric $SU(5)$ grand unification models are systematically derived. Restricted to extensions on $\mathbf{5}_{H}$ containing the Higgs sector we show that only two types of real (vector-like) models and one type of chiral model are found to be consistent with perturbative grand unification. While the chiral model has been excluded by the LHC data, the fate of perturbative unification will be uniquely determined by the two classes of vector-like models.

hep-ph↗

arXiv2017

Scalar Dark Matter: Real vs Complex

We update the parameter spaces for both a real and complex scalar dark matter via the Higgs portal. In the light of constraints arising from the LUX 2016 data, the latest Higgs invisible decay and the gamma ray spectrum, the dark matter resonant mass region is further restricted to a narrow window between $54.9-62.3$ GeV in both cases, and its large mass region is excluded until $834$ GeV and $3473$ GeV for the real and complex scalar, respectively.

hep-ph↗

arXiv2017

O'R Inflation in $F$-term Supergravity

The supersymmetric realization of inflation in $F$-term supergravity is usually plagued by the well known "$η$" problem. In this paper, a broad class of small-field examples is realized by employing general O' Raifeartaigh superpotentials, where the moduli is identified as the massless inflaton. For illustration we present the simplest example in detail, which can be considered as a generalization of hybrid inflation.

astro-ph.CO↗

arXiv2016

Higgs-portal Scalar Dark Matter: Scattering Cross Section and Observable Limits

The simplest Higgs-portal dark matter model is studied in the light of dark matter self-interacting effects on the formation of large scale structures. We show the direct detection limits on the resonant and large mass regions. Finally, we also compare these limits with those at the LHC and Xenon 1T experiments.

hep-ph↗

arXiv2016

Scalar Explanation of Diphoton Excess at LHC

Inspired by the diphoton signal excess observed in the latest data of 13 TeV LHC, we consider either a 750 GeV real scalar or pseudo-scalar responsible for this anomaly. We propose a concrete vector-like quark model, in which the vector-like fermion pairs directly couple to this scalar via Yukawa interaction. For this setting the scalar is mainly produced via gluon fusion, then decays at the one-loop level to SM diboson channels $gg, γγ, ZZ, WW$. We show that for the vector-like fermion pairs with exotic electric charges, such model can account for the diphoton excess and is consistent with the data of 8 TeV LHC simultaneously in the context of perturbative analysis.

hep-ph↗

arXiv2016

Collider Signatures of Higgs-portal Scalar Dark Matter

In the simplest Higgs-portal scalar dark matter model, the dark matter mass has been restricted to be either near the resonant mass ($m_h/2$) or in a large-mass region by the direct detection at LHC Run 1 and LUX. While the large-mass region below roughly 3 TeV can be probed by the future Xenon1T experiment, most of the resonant mass region is beyond the scope of Xenon1T. In this paper, we study the direct detection of such scalar dark matter in the narrow resonant mass region at the 14 TeV LHC and the future 100 TeV hadron collider. We show the luminosities required for the $2σ$ exclusion and $5σ$ discovery.

hep-ph↗

arXiv2016

Dark Matter Theories in the Light of Diphoton Excess

A new type of dark matter (DM) theories are proposed in the light of the standard model (SM) singlet scalar $ϕ$ which is responsible for the diphoton excess at the LHC Run 2. In the so-called $ϕ$-portal DM models, after taking into account the LHC constraints and DM direct detection limits, we show that in the perturbative framework DM as either a SM singlet scalar or Dirac fermion can be allowed in a wide mass range between 400 GeV and 3 TeV. The DM can be directly detected in SM multi-jets and missing energy.

hep-ph↗

arXiv2015

New Constraints on Higgs-portal Scalar Dark Matter

The simplest Higgs-portal scalar dark matter model, in which a real scalar singlet is added to the standard model, has been revisited, by taking into account the constraints from perturbativity, electroweak vacuum stability in the early Universe, dark matter direct detection, and Higgs invisible decay at the LHC. We show that the {\it resonant mass region} is totally excluded and the {\it high mass region} is reduced to a narrow window $1.1$ ~TeV $\leq m_{s} \leq$ $ 2.55$~ TeV, which is slightly reduced to $1.1$~TeV $\leq m_{s} \leq$ $ 2.0$~ TeV if the perturbativity is further imposed. This {\it high mass range} can be fully detected by the Xenon 1T experiment.

hep-ph↗