Collider signals of unparticle physics

Phenomenology of the notion of an unparticle U, recently perceived by Georgi, to describe a scale invariant sector with a nontrivial infrared fixed point at a higher energy scale is explored in details. Behaving like a collection of d(U) (the scale dimension of the unparticle operator O(U)) invisible massless particles, this unparticle can be unveiled by measurements of various energy distributions for the processes Z-->f f U and e- e+-->gammaU at e- e+ colliders, as well as monojet production at hadron colliders. We also study the propagator effects of the unparticle through the Drell-Yan tree-level process and the one-loop muon anomaly.     

Mini-bangs in cosmology and astrophysics

The ideas originally proposed to discuss continuous creation of matter are reconsidered in the context of the big bang cosmological models. It is shown that singularity-free big bang models are possible under the modified field equations of general relativity. However, the case is made out that matter creation takes place in several mini-bangs at different epochs rather than in one big bang. The implications of this idea for high energy astrophysics and for gravitational radiation are discussed.     

Isometric embeddings in cosmology and astrophysics

Recent interest in higher-dimensional cosmological models has prompted some significant work on the mathematical technicalities of how one goes about embedding spacetimes into some higher-dimensional space. We survey results in the literature (existence theorems and simple explicit embeddings); briefly outline our work on global embeddings as well as explicit results for more complex geometries; and provide some examples. These results are contextualized physically, so as to provide a foundation for a detailed commentary on several key issues in the field such as: the meaning of ‘Ricci equivalent’ embeddings; the uniqueness of local (or global) embeddings; symmetry inheritance properties; and astrophysical constraints.     

Neutrino masses in astrophysics and cosmology

Cosmology yields the most restrictive limits on neutrino masses and conversely, massive neutrinos would contribute to the cosmic dark-matter density and would play an important role for the formation of structure in the universe. Neutrino oscillations may well solve the solar neutrino problem and can have a significant impact on supernova physics. The neutrino signal from a future galactic supernova could provide evidence for cosmologically interesting neutrino masses or set interesting limits.     

Quark matter in astrophysics and cosmology

We discuss the role of quark matter in astrophysics and cosmology. The implications of the dynamics of the quark-hadron phase transition in the early universe for the element abundances from big gang nucleosynthesis and the composition of the dark matter in the universe are addressed. We discuss the possibility of deciding on an equation of state for high density matter by observing the cooling of a neutron star remnant of SN1987A. Quark matter models for the Centauros events, Cygnus X-3 cosmic ray events, high energy gamma-ray bursts and the solar neutrino problem are described.     

Another odd thing about unparticle physics

The peculiar propagator of scale invariant unparticles has phases that produce unusual patterns of interference with Standard Model processes. We illustrate some of these effects in e⁺e⁻→μ⁺μ⁻$e^{+}{e}^{-}\to {\mu }^{+}{\mu }^{-}$.     

Darkon dark matter, unparticle effects and collider physics

In this talk I report recent results on the simplest dark matter model, the Darkon model, and supersymmetric unparticle effects on dark matter, and some implications for coUider physics. I first discuss dark matter properties and collider signatures in the Darkon model, and then I discuss some implications for dark matter if a scalar unparticle is introduced to the MSSM.     

The reconciliation of physics with cosmology

Astronomical observations of redshifts and the cosmic background radiation show that there is a local frame of reference relative to which the solar system has a well-defined velocity. Also, in cosmology the cosmological principle implies the existence of cosmic time and unique local reference frames at all spacetime points. On the other hand, in a fundamental postulate, the theory of special relativity excludes the possibility of the velocity of the Earth from entering into theories of local physics.The theory put forward in this paper resolves this conflict between local physics and cosmology. The theory retains the essential ingredient of the mathematical structure of special relativity, namely covariance under the Lorentz symmetry group, but changes radically the interpretation of the physical significance of the Lorentz transformation. The theory is based on the postulate that in free space the fundamental interactions in physics are propagated with constant velocity with respect to the local rest frame. In Minkowski spacetime the local rest frame of reference defines a unique time axis and consequently a unique three-dimensional spatial hyperplane. One particularly important result of this is that the theory includes the classical notion of simultaneity. From the fundamental postulate it follows that the equations of local physics, when expressed in terms of the rest frame coordinate system, must be covariant under the Lorentz symmetry group. By the identification of the local rest frame with the (unique) cosmological local reference frame the two theories become mutually consistent.The effects of the motion of the Earth on laboratory experiments are discussed. It is pointed out that existing experimental data do not discriminate between the present theory and that of special relativity: a proposal for an experimental test is made.Address for the academic year 1990–1991: 415 Graduate Studies Research Center, University of Georgia, Athens, Georgia 30602.     

Darkon dark matter,unparticle effects and collider physics

In this talk I report recent results on the simplest dark matter model, the Darkon model, and supersymmetric unparticle effects on dark matter, and some implications for collider physics. I first discuss dark matter properties and collider signatures in the Darkon model, and then I discuss some implications for dark matter if a scalar unparticle is introduced to the MSSM.     

Notes on dark energy interacting with dark matter and unparticle in loop quantum cosmology

We investigate the behavior of dark energy interacting with dark matter and unparticle in the framework of loop quantum cosmology. In four toy models, we study the interaction between the cosmic components by choosing different coupling functions representing the interaction. We found that there are only two attractor solutions namely dark energy dominated and dark matter dominated Universe. The other two models are unstable, as they predict either a dark energy filled Universe or one completely devoid of it.     

Constraints on unparticle physics in electroweak gauge boson scattering

The existence of scale invariant physics would lead to new phenomena in particle physics that could be detected at the LHC. In this Letter we exploit the effects of these unparticles in WW→WW$WW\to WW$ scattering. From the requirement of unitarity we derive constraints on unparticle physics. We show that the existence of unparticles would lead to deviations in differential cross sections which can be measured. These deviations are sensitive on the scale dimension and on the spin characteristics of the unparticles.     

Neutrino physics from precision cosmology

Cosmology provides an excellent laboratory for testing various aspects of neutrino physics. Here, I review the current status of cosmological searches for neutrino mass, as well as other properties of neutrinos. Future cosmological probes of neutrino properties are also discussed in detail.     

Constraining new physics in with reparametrization invariance and QCD factorization

Usually, B⁰→π⁺π⁻ decays are expressed in terms of weak amplitudes explicitly dependent on the CKM weak phase α or γ. In this Letter, we show that the weak amplitudes can be rewritten such that a manifest dependence on β emerges instead. Based on this, we constrain new-physics contributions to the CP-violating phase _d in mixing. Further, we apply reparametrization invariance and use QCD factorization predictions to investigate the bounds on an additional new-physics amplitude in B⁰→π⁺π⁻.     

Quantum vacuum noise in physics and cosmology

The concept of the vacuum in quantum field theory is a subtle one. Vacuum states have a rich and complex set of properties that produce distinctive, though usually exceedingly small, physical effects. Quantum vacuum noise is familiar in optical and electronic devices, but in this paper I wish to consider extending the discussion to systems in which gravitation, or large accelerations, are important. This leads to the prediction of vacuum friction: The quantum vacuum can act in a manner reminiscent of a viscous fluid. One result is that rapidly changing gravitational fields can create particles from the vacuum, and in turn the backreaction on the gravitational dynamics operates like a damping force. I consider such effects in early universe cosmology and the theory of quantum black holes, including the possibility that the large-scale structure of the universe might be produced by quantum vacuum noise in an early inflationary phase. I also discuss the curious phenomenon that an observer who accelerates through a quantum vacuum perceives a bath of thermal radiation closely analogous to Hawking radiation from black holes, even though an inertial observer registers no particles. The effects predicted raise very deep and unresolved issues about the nature of quantum particles, the role of the observer, and the relationship between the quantum vacuum and the concepts of information and entropy. (c) 2001 American Institute of Physics.     

大学物理教学与现代天体物理的有机结合

2009年为国际天文年,在大学物理教学中有效融人现代天体物理知识是大学物理教师责无旁贷的任务.本文提出在教学中将第二宇宙速度与黑洞的引力半径、角动量守恒定律与脉冲星、磁通量与强磁场中子星、磁能密度与磁星进行有机结合,可提高广大学生的学习兴趣并激发他们的学习潜能.     

Constraints of unparticle physics parameters from K^0-^-K^0 mixing

The neutral kaon meson mixing plays an important role in the test of the Standard Model （SM） and new physics beyond it. Scale invariant unparticle physics induces a flavor changing neutral current （FCNC） transition of m K^0-^-K^0 oscillation at the tree level. In this study, we investigate the scale invariant unparticle physics effects on the m K^0-^-K^0 mixing. Based on the current experimental data, we give constraints of m K0-K0 mixing on the unparticle parameters.