117047620
Unitarity and Entropy Change in Exclusive Quark Combination Models
Entropy change in exclusive quark combination models is not an isolated problem. Contrary to adding and tuning some parameters to the relevant model(s) to fix the entropy, we show that it relates to the most general principles. Unitarity of the combination model is demonstrated to play the central r\^{o}le that guarantees the non-decrease of the entropy in the exclusive combination process.
115465221
OPERA Collaboration have observed phase speed of neutrino wave function, while advanced time displacement is mainly due to finite life time of pion
First we call the attention that velocity defined by ratio between some intervals of space and time respectively is sometimes ambiguous, in the framework of quantum theory. Velocity in general is not possible to be well defined as some generator of certain space-time symmetry operation. Then in section 3 by analyzing the OPERA experiment we show that the OPERA Collaboration may have measured the phase speed of the neutrino wave function. Employing a very (maybe too) simple model which is just a reproduction from Brillouin's classical book, we demonstrate the phase velocity and group velocity. These are just a qualitative illustration rather than aiming to quantitively explain the OPERA data. However, how to rigorously define the phase containing the particle production ordering information as a space-time distribution observable in QFT needs more investigations. Due to the finite life time of the pions (w.r.t. its flying time in the 1 km long tunnel) which decay to the muon neutrinos, the wave form for neutrinos recorded by OPERA is deformed from that of the proton. Such an effect is estimated to lead to an advanced time displacement of the order of 100ns, which coincides with the measured. Such an effect can only be significant when measuring phase speed and the recorded neutrino events per extraction of proton smaller than one, as the OPERA case.
54545936
Multirefringence phenomena in nonlinear electrodynamics
Universite´ de Nice Sophia Antipolis, 06103 Nice Cedex 2, Franceand Dipartimento di Fisica and ICRA, Sapienza Universita` di Roma, I-00185 Rome, Italy(Received 19 April 2013; published 13 September 2013)Wave propagation in nonlinear theories of the electromagnetism described by Lagrangian densitiesdependent upon its two local invariants LðF;GÞ is revisited. On the light of the recent ﬁndings inmetamaterials, it is here shown that trirefringence is also a possible phenomenon to occur in the realm ofsuch nonlinear theories. A speciﬁc model exhibiting this effect is investigated in terms of both phase andgroup velocities. It is claimed that wave propagation in some well known nonlinear models for spin-oneﬁelds, like QED and QCD in certain regimes, may exhibit trirefringence.
118901774
Gluon Shadowing and Hadron Production at RHIC
Nuclear Science Division, Mailstop 70-319, Lawrence Berkeley Laboratory, Berkeley, California 94720.(October 3,2001)Hadron multiplicity in the central rapidity region of high-energy heavy-ion collisions is investi-gated within a two-component mini-jet model which consists of soft and semi-hard particle produc-tion. The hard contribution from mini-jets is reevaluated using the latest parameterization of partondistributions and nuclear shadowing. The energy dependence of the experimental data from RHICrequires a strong nuclear shadowing of the gluon distribution in this model. The centrality depen-dence of the hadron multiplicity at√s = 130 GeV is reproduced well with the impact-parameterdependent parton shadowing. However, energy variation of the centrality dependence is needed todistinguish diﬀerent particle production mechanisms such as the parton saturation model.25.75.-q,12.38.Bx,12.38.Mh,24.85.+p
13962394
Combination of Heavy Quark with Partons from Quark-Gluon Matter: a Scaling Probe
In relativistic heavy ion collisions, the cross section of heavy hadron production via the combination of a heavy quark with a light one from the quark-gluon matter can be factorized. It is the convolution of twist-4 combination matrix elements, the parameters corresponding to the parton distributions of the quark-gluon matter, as well as the hard partonic cross section of heavy quark production calculable in PQCD. These parton distributions and combination matrix elements are functions of a scaling variable which is the momentum fraction of the heavy quark w.r.t. the heavy hadron. In the same factorization framework, the combination matrix elements appear in other `simpler' processes and can be extracted. Taking them as inputs, comparing with data from RHIC and (future) LHC, we can get the parton distributions of the quark-gluon matter just as the similar way we get those of nucleon, pion, or photon, etc..
119531071
Comments on CLEO new measurements for $\upsilon_{1S}$ decays to charmonium final states and investigations on associate strange particle enhancement in $\upsilon$ to J/Psi + $X$
The recent measurements by CLEO Collaboration for the inclusive J/Psi and Psi(2S) production in Upsilon(1S) decay and our previous calculation are analyzed. The J/Psi momentum spectrum and the production ratio of Psi(2S) versus J/Psi favour Upsilon to J/Psi(Psi(2S)) + ccbar g as the dominant contribution. We point out that the differences between the experimental data and our previous results are mainly originated from the setting of the parameter charm quark mass. We further suggest the associate strange particle enhancement as a probe for the open charm particles in Upsilon to J/Psi (Psi(2S)) + ccbar g.
118371112
Observational constraints on Tachyon and DBI inflation
We present a systematic method for evaluation of perturbation observables in non-canonical single-field inflation models within the slow-roll approximation, which allied with field redefinitions enables predictions to be established for a wide range of models. We use this to investigate various non-canonical inflation models, including Tachyon inflation and DBI inflation. The Lambert function will be used extensively in our method for the evaluation of observables. In the Tachyon case, in the slow-roll approximation the model can be approximated by a canonical field with a redefined potential, which yields predictions in better agreement with observations than the canonical equivalents. For DBI inflation models we consider contributions from both the scalar potential and the warp geometry. In the case of a quartic potential, we find a formula for the observables under both non-relativistic (sound speed cs2 ~ 1) and relativistic behaviour (cs2 1) of the scalar DBI inflaton. For a quadratic potential we find two branches in the non-relativistic cs2 ~ 1 case, determined by the competition of model parameters, while for the relativistic case cs2 → 0, we find consistency with results already in the literature. We present a comparison to the latest Planck satellite observations. Most of the non-canonical models we investigate, including the Tachyon, are better fits to data than canonical models with the same potential, but we find that DBI models in the slow-roll regime have difficulty in matching the data.
119232075
Renormalization group improved predictions for $t\bar{t}W^\pm$ production at hadron colliders
We study the factorization and resummation of the $t\bar{t}W^\pm$ production at hadron colliders. The cross section in the threshold limit can be factorized into a convolution of hard and soft functions and parton distribution functions with the soft-collinear effective theory. We calculate the next-to-leading order soft function for the associated production of the heavy quark pair and colorless particle, and we perform the resummation calculation with the next-to-next-to-leading logarithms accuracy. Our results show that the resummation effects reduce the dependence of the cross section on the scales significantly and increase the total cross section by $7-13\%$ compared with NLO QCD results.
18661974
Decomposition Theory of Spin Connection and Topological Structure of Gauss-Bonnet-Chern Theorem on Manifold With Boundary
The index theorem of Euler-Poincar\'e characteristic of manifold with boundary is given by making use of the general decomposition theory of spin connection. We shows the sum of the total index of a vector field $\phi $ and half the total of the projective vector field of $\phi $ on the boundary equals the Euler-Poincar\'e characteristic of the manifold. Detailed discussion on the topological structure of the Gauss-Bonnet-Chern theorem on manifold with boundary is given. The Hopf indices and Brouwer degrees label the local structure of the Euler density.
118396850
SO(4) monopole as a new topological invariant and its topological structure
By making use of the decomposition theory of gauge potential, the inner structure of SU(2) and SO(4) gauge theory is discussed in detail. We find the SO(4) monopole can be given via projecting the SO(4) gauge field onto an antisymmetric tensor. This projection fix the coset $% SU(2)/U(1)\bigotimes SU(2)/U(1)$ of SO(4) gauge group. The generalized Hopf map is given via a Dirac spinor. Further we prove that this monopole can be consider as a new topological invariant. Which is composed of two monopole structures. Local topological structure of the SO(4) monopole is discussed in detail, which is quantized by winding number. The Hopf indices and Brouwer degree labels the local property of the monopoles.
118488945
Current leads for superconducting magnets of ADS injector I
In an ADS injector I, there are five superconducting magnets in each cryomodule. Each superconducting magnet contains a solenoid magnet, a horizontal dipole corrector (HDC), and a vertical dipole corrector (VDC). Six current leads will be required to power the electrical circuits, from room temperature to the 2.1 K liquid helium bath: two leads carry 100 A current for the solenoid magnet while the other four carry 12 A for the HDC and the VDC. This paper presents the principle of current lead optimization, which includes the cooling methods, the choice of material and structure, and the issues for current lead integration.