40224148
Virtual effects of split-SUSY in Higgs productions at linear colliders
In split supersymmetry, gauginos and higgsinos are the only supersymmetric particles possibly accessible at foreseeable colliders like the CERN Large Hadron Collider (LHC) and the International Linear Collider (ILC). In order to account for the cosmic dark matter measured by WMAP, these gauginos and higgsinos are stringently constrained and could be explored at the colliders through their direct productions and/or virtual effects in some processes. The clean environment and high luminosity of the ILC render the virtual effects at percent level meaningful in unraveling the new physics effects. In this work we assume split supersymmetry and calculate the virtual effects of the WMAP-allowed gauginos and higgsinos in the Higgs productions e+e-→Zh and e+e-→νeν̄eh through WW fusion at the ILC. We find that the production cross section of e+e-→Zh can be altered by a few percent in some part of the WMAP-allowed parameter space, while the correction to the WW fusion process e+e-→νeν̄eh is below 1%. Such virtual effects are correlated with the cross sections of chargino pair productions and can offer complementary information in probing split supersymmetry at the colliders.
14236612
Late-decaying Q-ball with BBN lifetime
In the Affleck-Dine mechanism of baryogenesis, nontopological solitons called Q-balls can be formed. In this work we propose that such Q-balls decay during the BBN era and study the cosmological consequence of such late decays. We find that the late-decaying baryonic Q-balls with lifetime of about 10(3) s can provide a new developing mechanism for the BBN through a rolling baryon-to-photon ratio eta, which can naturally explain the discrepancy of the BBN prediction with the WMAP data on Li-7 abundance. For the late-decaying leptonic Q-balls with lifetime of about 10(6) s, we find that their decay product, gravitinos, can serve as a dark matter candidate and give an explanation for the approximate equality of dark and baryon matter densities. (C) 2004 Elsevier B.V. All rights reserved.
43093269
Rare decays of the top quark in the one generation technicolor model.
The decays [ital t][r arrow][ital cV] ([ital V]=[gamma],[ital g],[ital Z]) and [ital t][r arrow][ital cP][sup 0] induced through loop processes are calculated in the Farhi-Susskind one family technicolor (TC) model. We find that these new contributions can enhance the SM branching fractions by as much as 3--4 orders of magnitude, i.e., [ital B]([ital t][r arrow][ital cg])[similar to]10[sup [minus]6], [ital B]([ital t][r arrow][ital cZ])[similar to]10[sup [minus]7], [ital B]([ital t][r arrow][ital c][gamma])[similar to]10[sup [minus]8], and [ital B]([ital t][r arrow][ital cP][sup 0])[similar to]10[sup [minus]9], for the favorable values of the parameters. It might provide a unique window to detect the virtual effects of pseudo Goldstone bosons in TC theory.
118656803
Realistic flipped SU(5) from orbifold SO(10)
We propose a realistic flipped SU(5) model derived from a five-dimensional orbifold SO(10) model. The Standard Model (SM) fermion masses and mixings are explained by combining the traditional Froggatt-Nielsen mechanism with the five-dimensional wave function profiles of the SM fermions. Employing tree-level spontaneous R-symmetry breaking in the hidden sector and extra(ordinary) gauge mediation, we obtain realistic supersymmetry breaking soft mass terms with non-vanishing gaugino masses. Including the messenger fields at the intermediate scale and Kaluza-Klein states at the compactification scale, we study gauge coupling unification. We show that the SO(10) unified gauge coupling is very strong and the unification scale can be much higher than the compactification scale. We briefly discuss proton decay as well.
123678213
Rare decays of the top quark in the technicolour model with a massless scalar doublet
The rare decays induced through loop processes are calculated in a minimal technicolour model (MTC) with a massless weak doublet recently presented by Carone and Georgi. We find that these new contributions can enhance the standard model branching fractions by as much as three to four orders of magnitude, i.e. , , for favourable values of the parameters. This might provide a unique window to detect the virtual effects of technipions in MTC theory.
10548822
Supersymmetric electroweak corrections to top quark production at the Fermilab Tevatron.
10538446
Why have Higgs particles not been found yet
It is suggested that within the effective potential approach, convex-ity and spontaneous symmetry breaking(SSB) make the Higgs bosons bizarre and experimentally nonexistent, a possible resolution of the Higgs puzzle. This observation might have quite some nontrivial consequences for the Standard Model (SM) and particle physics. By now, the experimentally nonexistence of Higgs particles predicted by the SM has become a puzzle in spite that the SM has been deemed as well established by the community of high energy physics (HEP), especially given that the estimated mass range of Higgs bosons has already become accessible [1]. There can be found a number of attempts to explain this puzzling situation. There is even modeling work trying to provide masses for intermediate gauge bosons without introducing Higgs model [2]. In this report, We attempt to suggest an alternative way of looking at this problem still within the SM theory. We will adopt the effective potential 1
12618841
Antishadowing effects in the unitarized BFKL equation
Abstract A unitarized BFKL equation incorporating shadowing and antishadowing corrections of the gluon recombination is proposed. This equation reduces to the Balitsky–Kovchegov evolution equation near the saturation limit. We find that the antishadowing effects have a sizable influence on the gluon distribution function in the preasymptotic regime.
14573379
Harmonic scaling laws and underlying structures
Based on the effective field theory philosophy, a universal form of the scaling laws could be easily derived with the scaling anomalies naturally clarified as the decoupling effects of underlying physics. In the novel framework, the conventional renormalization group equations and Callan-Symanzik equations could be reproduced as special cases and a number of important and difficult issues around them could be clarified. The underlying theory point of view could envisage a harmonic scaling law that help to fix the form of the loop amplitudes through anomalies, and the heavy field decoupling can be incorporated in this underlying theory approach in a more unified manner.
7709022
Finiteness following from underlying theory: a natural strategy
A tentative proposal is demonstrated that there is a natural strategy to get rid of unphysical (UV) infinities in QFTs if one adopts the modern standard point of view that a fundamental theory that is complete and well-defined in all respects underlies the QFTs. This simple strategy works in principle for any interaction model and space-time dimension. It provides a physical rationality behind the UV divergence and the conventional renormalization programs and improves the latter in several important aspects.
117884871
Coarse graining and renormalization
Formulating the QFT's as coarse grained 'low' energy sectors of a postulated complete quantum theory of everything with the 'high' energy modes integrated out or 'clustering' into 'low' energy objects, we can evaluate the Feynman amplitudes by solving a series of natural differential equations which automatically dissolves the necessity of infinity subtraction and the associated subtleties. This new strategy has direct implications to the scheme dependence problem.