A multi-charged particle model with local U(1)_(μ-τ) to explain muon g-2,flavor physics,and possible collider signature

We consider a model with multi-charged particles,including vector-like fermions,and a charged scalar under a local U(1)_(μ−τ) symmetry.We search for an allowed parameter region explaining muon anomalous magnetic moment(muon g−2)and b→sℓ^(+)ℓ^(−) anomalies,satisfying constraints from the lepton flavor violations,Z boson decays,meson anti-meson mixing,and collider experiments.Via numerical analysis,we explore the typical size of the muon g−2 and Wilson coefficients to explain the b→sℓ^(+)ℓ^(−) anomalies in our model when all other experimental constraints are satisfied.Subsequently,we discuss the collider physics of the multicharged vectorlike fermions,considering a number of benchmark points in the allowed parameter space.

ACCELERATOR PHYSICS OF COLLIDERS

Revised August 2013 by M.J. Syphers （MSU） and F. Zimmermann （CERN）.29.1. Luminosity This article provides background for the High-Energy Collider Parameter Tables that follow. The number of events, Nexp, is the product of the cross section of interest,

Probing top-philic new physics via four-top-quark production

We explore constraints on various new physics resonances from four top-quark production based on current experimental data.Both light and heavy resonances are studied in this work.A comparison of the full width effect and narrow width approximation is also presented.

New physics and two boosted W-jets plus missing energy

We show that the signature of two boosted W-jets plus substantial missing energy is very promising for probing heavy charged resonances(X^(±))through the process of pp→X^(+)X^(-)→W^(+)W^(-)X^(0) X^(0),where X^(0) denotes the dark matter candidate.The hadronic decay mode of the W boson is considered to maximize the number of signal events.When the mass split between X±and X0 is large,the jet-substructure technique must be utilized to analyze the boosted W-jet.Here,we consider the process of chargino pair production at the LHC,i.e.,pp→χ^(+)_(1)χ^(-)_(1)→W^(+)W^(-)χ^(0)_(1)χ^(0)_(1),and demonstrate that the proposed signature is able to cover more parameter space of m_(χ1)^(±)and m_(χ1)0,than the conventional signature of multiple leptons plus missing energy.More importantly,the signature of interest is not sensitive to the spin of heavy resonances.

Searching for the axion-like particle at the EIC

The axion-like particle(ALP)is a well motivated new particle candidate for beyond the standard model.In this study,we propose to probe the ALP via photon fusion scattering at the upcoming Electron-Ion Collider(EIC)with electron and proton energies of E_(e)=20 GeV and E_(p)=250 GeV,respectively.We can constrain the effective coupling strength between the ALP and photons to be 0.2 TeV^(-1)at the 2σconfidence level with an integrated luminosity of 300 fb^(-1)for the mass range m_(a)∈[5,40]GeV.Such bounds may be significantly improved if we consider the nucleus beam at the EIC.We also demonstrate that the limits from the EIC can be stronger than the off Zpole measurement at the LEP and light-by-light scattering with pp collisions at the LHC.

What can we learn from the total width of the Higgs boson?

As one of the key properties of the Higgs boson, the Higgs total width is sensitive to the global profile ofthe Higgs boson couplings, and thus new physics would modify the Higgs width. We investigate the total width invarious new physics models, including various scalar extensions, composite Higgs models, and the fraternal twinHiggs model. Typically, the Higgs width is smaller than the standard model value due to mixture with other scalarsif the Higgs is elementary, or curved Higgs field space for the composite Higgs. On the other hand, except for thepossible invisible decay mode, the enhanced Yukawa coupling in the two Higgs doublet model or the exotic fermionembeddings in the composite Higgs could enhance the Higgs width greatly. The precision measurement of the Higgstotal width at the high-luminosity LHC can be used to discriminate certain new physics models.

A private SUSY 4HDM with FCNC in the up-sector

We present a SUSY model with four Higgs doublets of the"private type,"in which all fermion types(up,down,and charged leptons)obtain their masses from a different Higgs doublet H_f(f=u_1,d,e) .The conditions for anomaly cancellation imply that the remaining Higgs doublet of the model( H_(u_2) )must have the same hypercharge as H_(u_1) ,and thus,can only couple to up-type quarks,which opens the possibility to have FCNCs only in this sector.We study the Lagrangian of the model,and in particular,the Higgs potential,to identify the Higgs mass-eigenstates and their interactions;for the Yukawa matrices,we consider the four-texture case.We obtain constraints on the model parameters by using LHC measurements on the properties of the 125 GeV Higgs boson(h),and identify viable regions of the parameter space.Subsequently,these constraints are used to evaluate the prospects for detecting the FCNC decay mode t→ch at the future high-luminosity(HL)option for the LHC,which are compared with current limits from LHC-run2.Moreover,we evaluate the FCNC decay of the next heavier Higgs boson H_(2)→tc ,which can typically reach BR(H_2→tc)≈(10^(-4)-10^(-5)) .The search for the signal at HL-LHC is also studied,and it is found that it may be detectable for specific regions of the model parameter space.