46718592
Nambu-Goldstone bosons and dynamical symmetry breaking in QCD at high temperatures.
We report on the renormalization-group study of the low-energy effective potential in QCD. We derive the dynamically induced linear {sigma} model (DSM), whose self-couplings are not free parameters but are determined in terms of the running coupling of the underlying QCD. In this DSM, the {sigma} meson is not a fundamental field, but a genuine quark-antiquark 0{sup +} bound state, while the {pi} is the quark-antiquark 0{sup {minus}} bound state. We show the masslessness of the {pi} at zero temperature, so that the {pi} is a true Nambu-Goldstone boson coupled to zero-temperature chirality. At high temperatures, the {pi} remains massless. Thus the zero-temperature chirality is not restored at high temperatures. The apparent chiral symmetry operative at high temperatures is thus to be distinguished from that at {ital T}=0. Comparison is made with the situation in the BCS and other theories where symmetry restoration does indeed take place.
121599412
Decoupling renormalization and hierarchies
We introduce the decoupling renormalization scheme for the one-particle irreducible Green's functions of a theory that has a mass hierarchy. The decoupling-subtraction renormalization-group equations respect a tree-level hierarchy. Thus, fine tuning is to be done only at the tree level.
122809875
FIVE DECADES AFTER THE REVOLUTION: HOW MUCH DO WE KNOW ABOUT THE NEUTRINO?
It is a pleasure to dedicate this talk to Prof Yang on the occasion of his 85th birthday, especially here in my birthplace, Singapore. I still recall the year 1957 when the local Chinese newspapers broke with the story of breakdown of parity, I didn’t understand the phrase , and when I checked into my high school physics text, I couldn’t find any explanation. The Chinese newspapers , call this Lee–Yang breakthrough a revolution, but it was hardly noticed by the English newspapers at the time. It wasn’t until I came to the U.S. in the Fall of 1957, that a true revolution occurred. I think I can speak for a whole generation of ethnic Chinese physicists who grew up in the U.S. that we personally benefitted far more from this revolution than the revelation of parity non-conservation.
18392660
Chirality in the Early Universe
The early big bang is an alphabet soup of quarks, W bosons, gluons, and other exotic particles and flavors. In the usual scenario, there is no place for the pion. It dissociates in the alphabet soup of the early universe. I will show that this scenario is naive. The thermal vacuum is a far more complex state, and the pion remains a Nambu-Goldstone particle at high $T$, and will not dissociate. It propagates at the speed of light but {\em with a halo}.
120226155
Impact parameters: A geometrical picture of inelastic scattering
Abstract The constraints on the impact-parameter description of arbitrary n -body scattering due to the Lorentz group are shown to take a simple form at very high energies. The produced jet of beam fragmentation products, each with b i , and x i , will be centered about the impact parameter b of the incident beam. A geometrical language can be introduced for the description of inelastic scattering and a simple model is proposed based on this picture. The single-fragmentation inclusive cross section is shown to rise as log s if the total cross section rises as log-squared. In a bremsstrahlung-type model, it is shown that an energy-dependent eikonal of the Cheng-Wu type can be compatible with the apparently linear fit to the Wroblewski plot.
119847840
Linear Regge trajectories for the psion family and O(4) dynamics
The newly discovered psion family can be described by mass-squared linear Regge trajectories. The new J/subP//subC/ assignments are for 2.8 GeV/ c$sup 2$, 0$sup ++$, and for the 3.4 region, 2$sup ++$, 1$sup -+$, 0$sup ++$. All radiative decays are related through a single S/sub mu//sub nu/F/sub mu//sub nu/ coupling. A good fit is obtained. (AIP)
11075073
Generalized Jaynes-Cummings model with an intensity-dependent coupling interacting with a quantum group-theoretic coherent state.
We present a generalized Jaynes-Cummings model (JCM) with an intensity-dependent coupling interacting with a quantum group-theoretic coherent state. The field operators of the JCM Hamiltonian are identified as the elements of the su(q)(1,1) quantum algebra in their Holstein-Primakoff realizations. We lay emphasis on the time evolution of field quadruatures and atomic population inversion of the generalized JCM. The revivals of radiation squeezing are obtained for any values of initial squeezing.
38291756
Quantum critical phenomena and conformal invariance.