648376
Harmonic scale transformation in effective QFTs with underlying structures
New equations governing the scale transformation behaviors of a QFT with underlying structures are derived. These equations, with their several equivalent versions, can yield some new and significant insights and results that are difficult to see in the conventional renormalization programs. Among the several equivalent versions, one is similar to the usual Callan-Symanzik equation and renormalization group equation but with different meanings. From another version, the anomalous equation of energy-momentum tensor trace can be easily obtained. It can be shown that with the new versions one could partially fix the scheme dependence and hence some renormalization schemes like momentum space subtractions are questionable. The asymptotic freedom for QCD is easily reproduced at one-loop level in our new version CSE. Finally the decoupling theorem a la Appelquist and Carazzone are discussed within our strategy.
15356070
Can QFT be UV finite as well as effective
A new attempt is demonstrated that QFTs can be UV finite if they are viewed as the low energy effective theories of a fundamental underlying theory (complete and well-defined in all respects) according to the modern standard point of view. This approach is much simpler in principle and in technology comparing to any known renormalization program. Some subtle and difficult issues can be easily resolved. The importance of the procedure for defining the ambiguities is fully appreciated in the new approach. Some simple but important nonperturbative examples are discussed to show the power and plausibility of the new approach.
14239579
Confinement of Higgs bosons from hidden symmetry and convexity
In the full effective potential (EFP) approach, we find that spontaneous symmetry breaking (SSB) can, with the convexity of the full EFP, lead to the prediction of the IR confinement of Higgs particles, adding difficulty to the experimental identification of Higgs particles. The short distance behaviors remain intact. The whole presentation is given in the understanding that any QFT becomes UV well defined in a more complete underyling theory according to a recently proposed strategy.
13049479
A new kind of constraints on renormalization schemes
We derive a new kind of physical constraints on the subtraction schemes for theories with massive particles in addition to the Ward identities for gauge symmetries. The momentum subtraction scheme fails this criterion. The decoupling of heavy fields is discussed in the context of Callan-Symanzik equations where all schemes (including MOM) lead to the same pattern of decoupling with inevitable discontinuities in beta function across heavy field thresholds. PACS number(s): 11.10.Gh; 11.10.Hi; 12.39.Hg
119670186
Padé Expansion and the Renormalization of Nucleon–Nucleon Scattering
The importance of imposing physical boundary conditions on the T-matrix to remove the nonperturbative renormalization prescription dependence is stressed and demonstrated in two diagonal channels 1P1 and 1D2, with the help of Pade expansion.
120520076
Soliton mass and discrete coupling constants in the quantized sine-Gordon model
The soliton mass in the quantized sine-Gordon model over the whole range of the coupling constant (g2 from 0 to 8 pi ) is evaluated by means of the Gaussian effective potential method. The analytical expression with numerical results is presented. The authors find that the coupling constant g can only take discrete values. A new kind of soliton linking g Phi =0 to g Phi = pi emerges at a set of special coupling constants g.
123786693
SUSY virtual effects on the production of t anti-q at LEP-2
Virtual effects of supersymmetry on the flavor changing process at LEPII are calculated in the minimal supersymmetric standard model (MSSM). We analyze the cross section of , and find that even for the most distinguishable mode , the effect is small compared with the SM expectation.
125953408
Virtual effects of charged pseudoGoldstone bosons on $Z b \bar{b}$ vertex
118390410
Light dark matter from the U(1)(X) sector in the NMSSM with gauge mediation
Cosmic ray anomalies observed by PAMELA and Fermi-LAT experiments may be interpreted by heavy (TeV-scale) dark matter annihilation enhanced by Sommerfeld effects mediated by a very light (sub-GeV) U(1)(X) gauge boson, while the recent direct searches from CoGeNT and DAMA/LIBRA experiments may indicate a rather light (similar to 7GeV) dark matter with weak interaction. Motivated by these apparently different scales, we consider a gauge mediated next-to-the minimal supersymmetric standard model (NMSSM) entended with a light U(1)(X) sector plus a heavy sector ((H) over barh, Hh), which can provide both a light (similar to 7GeV) and a heavy (TeV-scale) dark matter without introducing any ad hoc new scale. Through the Yukawa coupling between Hh and the messager fields, the U(1)(X) gauge symmetry is broken around the GeV scale radiatively and a large negative m(S)(2) is generated for the NMSSM singlet S. Furthermore, the small kinetic mixing parameter between U(1)(X) and U(1)(Y) is predicted to be theta similar to 10(-5) - 10(-6) after integrating out the messengers. Such a light dark matter, which can have a normal relic density from the late decay of the right-handed sneutrino (assumed to be the ordinary next-to-the lightest supersymmetric particle and thermally produced in the early Universe), can serve a good candidate to explain the recent CoGeNT and DAMA/LIBRA results.
15717462
Dimension-six CP-violating operators of the third-family quarks and their effects at colliders
We list all possible dimension-six $\mathrm{CP}$-violating ${\mathrm{SU}}_{c}(3)\ifmmode\times\else\texttimes\fi{}{\mathrm{SU}}_{L}(2)\ifmmode\times\else\texttimes\fi{}{\mathrm{U}}_{Y}(1)$-invariant operators involving the third-family quarks, which can be generated by new physics at a higher energy scale. The expressions of these operators after electroweak symmetry breaking and the induced effective couplings $\mathrm{Wt}\overline{b}$, $\mathrm{Xb}\overline{b}$, and $\mathrm{Xt}\overline{t}$ $(X=Z,\ensuremath{\gamma},g,H)$ are also presented. We evaluate sample contributions of these operators to $\mathrm{CP}$-odd asymmetries of transverse polarization of the top quark in single top quark production at the upgraded Fermilab Tevatron, the same polarization effect in top-quark\char21{}top-antiquark pair production at the NLC, and the $\mathrm{CP}$-odd observables of momentum correlations among the top quark decay products at the NLC. The energy and luminosity sensitivity in probing this $\mathrm{CP}$-violating new physics is also studied.
118344505
PROBING NEW PHYSICS FROM TOP QUARK FCNC PROCESS AT LHC: A MINI REVIEW
Since the top quark FCNC processes are extremely supressed in the Standard Model (SM) but could be greatly enhanced in some new physics models, they could serve as a smoking gun for new physics hunting at the LHC. In this brief review we summarize the new physics predictions for various top quark FCNC processes at the LHC by focusing on two typical models: the minimal supersymmetric model (MSSM) and the topcolor-assisted technicol or (TC2) model. The conclusion is: (1) Both new physics models can greatly enhance the SM predictions by several orders; (2) The TC2 model allows for largest enhancement, and for each channel the maximal prediction is much larger than in the MSSM; (3) Compared with the 3 sigma sensitivity at the LHC, only a couple of channels are accessible for the MSSM while most channles are accesible for the TC2 model.