125152552
Negative Vertex Contributions to Parameters S and T From Charged Pseudo-Goldstone Boson*
We describe how to incorporate the one-loop vertex corrections on coming from the virtual charged pseudo-Goldstone bosons (PGB) and in one-generation technicolor model into the estimation for the value of Peskin–Takeuchi parameters S and T. We find that the vertex contributions SV and TV are all negative and can cancel out the positive oblique contributions Shad and Thad. Now the value of S can be negative and T is also much smaller than the traditional estimation.
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.
14268595
Phase transition of finite size quark droplets with isospin chemical potential in the Nambu–Jona-Lasinio model
Making use of the Nambu\char21{}Jona-Lasinio model and the multiple reflection expansion approximation, we study the phase transition of the finite size droplet with $u$ and $d$ quarks. We find that the dynamical masses of $u$, $d$ quarks are different, and the chiral symmetry can be restored at different critical radii for $u$, $d$ quarks. It provides a clue to understanding the effective nucleon mass splitting in nuclear matter. Meanwhile, it shows that the maximal isospin chemical potential at zero temperature is much smaller than the mass of pion in free space.
122968394
Multiscale technicolor and top quark decay
118036569
Detecting Toppion via a Flavor-Changing Single Top QuarkProduction Process*
In the framework of topcolor-assisted technicolor (TC2) theory, we study a flavor changing single top quarkproduction process pp(pp) →Ⅱ0t → tc(tc) at upgraded Tevatron and LHC. The results show that with the flavor changingcoupling of neutral toppion to top and charm quark, toppion provides a large te-channel resonance effect. The signal ofsingle top production could be detected at LHC. Otherwise, the narrow peak in the invariant mass distribution could beclearly detected both at upgraded Tevatron and LHC. Therefore, such single top production process provides a uniqueway to test TC2 model via the detection of tc-channel neutral toppion contribution.
119099946
The Flavor-changing bottom and anti-strange quark production in the littlest Higgs model with T parity at the ILC
In the littlest Higgs model with T-parity (LHT) the mirror quarks induce the special flavor structures and some new flavor-changing (FC) couplings which could greatly enhance the production rates of the FC processes. We in this paper study some bottom and anti-strange production processes in the LHT model at the International Linear Collider (ILC), i.e., $e^+e^-\to b\bar{s}$ and $\gamma\gamma\to b\bar{s}$. The results show that the production rates of these processes are sizeable for the favorable values of the parameters. Therefore, it is quite possible to test the LHT model or make some constrains on the relevant parameters of the LHT through the detection of these processes at the ILC.
3066888
Global quark polarization in non-central A+A collisions
Partons produced in the early stage of non-central heavy-ion collisionscan develop a longitudinal fluid shear because of unequal local number densities of participant target and projectile nucleons. Under such fluid shear, local parton pairs with non-vanishing impact parameter have finite local relative orbital angular momentum along the direction opposite to the reaction plane. Such finite relative orbitalangular momentum among locally interacting quark pairs can lead to global quark polarization along the same direction due to spin-orbital coupling. Local longitudinal fluid shear is estimated within both Landau fireball and Bjorken scaling model of initial parton production. Quark polarization through quark-quark scatterings with the exchange of a thermal gluon is calculated beyond small-angle scattering approximation in a quark-gluon plasma. The polarization is shown to have a non-monotonic dependence on the local relative orbital angular momentum dictated by the interplay between electric and magnetic interaction. It peaks at a value of relative orbital angular momentum which scales with the magnetic mass of the exchanged gluons. With the estimated small longitudinal fluid shear in semi-peripheral Au+Au collisions at the RHIC energy, the final quark polarization is found to be small left hbar P_q right hbar <0.04 in the weak coupling limit. Possible behavior of the quark polarization in the strong coupling limit and implications on the experimental detection of such global quark polarization at RHIC and LHC are also discussed.
20087962
Research on DC-clearing electric field and changes of focusing structure parameters of storage ring
This paper presents DC clearing field to clear ions in vacuum pipe of Hefei ring. It also presents changes of focusing structure parameters caused by the clearing field. It concludes that tune shifts caused by the field are related to real-time closed orbit of the beam. The paper points out that the field asymmetrically distributed along the ring destroys the symmetry of focusing structure and decreases the ring acceptance, which has negative effect to injection and accumulation process in certain condition.
54664229
Interference effect in elastic parton energy loss in a finite medium
Abstract Similar to the radiative parton energy loss due to gluon bremsstrahlung, elastic energy loss of a parton undergoing multiple scattering in a finite medium is demonstrated to be sensitive to interference effect. The interference between amplitudes of elastic scattering via a gluon exchange and that of gluon radiation reduces the effective elastic energy loss in a finite medium and gives rise to a non-trivial length dependence. The reduction is most significant for a propagation length L 4 / π T in a medium with a temperature T . Though the finite size effect is not significant for the average parton propagation in the most central heavy-ion collisions, it will affect the centrality dependence of its effect on jet quenching.
122691076
Localized electrons in a magnetic field
We briefly review recent developments on the response of localized electrons to an external magnetic field. They originate from subtle interference effects between forward-scattered paths which, in the localized regime, make the dominant contribution to the transition amplitude. On a lattice the correlations between the paths produce self-similar (quasiperiodic) spatial interference patterns for commensurate (incommensurate) ratios of the applied magnetic flux per plaquette with the flux quantum. If localization is due to strong disorder (as in lightly doped semiconductors), this is augmented by a logarithmic averaging. They give rise to striking quantum interference phenomena observed in mesoscopic and macroscopic insulators: Aharonov-Bohm oscillations with periods of one and one half flux-quantum, the Hall effect, pronounced conductance fluctuations, and anomalous negative (and positive in presence of spin-orbit scattering) magnetoresistance. The theoretical works based on the “directed paths” approach ...
118559274
Spin-Orbit Interaction of Nuclear Shell Structure
Single particle spin-orbit interaction energy problem in nuclear shell structure is solved through negative harmonic oscillator in the self-similar-structure shell model (SSM) [4] and considering quarks' contributions on single particle spin and orbit momentum. The paper demonstrates that single particle motion in normal nuclei is described better by SSM negative harmonic oscillator than conventional shell model positive harmonic oscillator[1][2][3]. The proposed theoretical formula for spin orbit interaction energy agrees well to experiment measurements.