A Note on Solid-State Maxwell Demon

Starting from 2002, at least two kinds of laboratory-testable, solid-state Maxwell demons have been proposed that utilize the electric field energy of an open-gap n-p junction and that seem to challenge the validity of the Second Law of Thermodynamics. In the present paper we present some arguments against the alleged functioning of such devices.Comment: 9 pages, 4 figures. Foundations of Physics, forthcoming. arXiv admin note: substantial text overlap with arXiv:1101.505

Constraints on the parameters of the Left Right Mirror Model

We study some phenomenological constraints on the parameters of a left right model with mirror fermions (LRMM) that solves the strong CP problem. In particular, we evaluate the contribution of mirror neutrinos to the invisible Z decay width (\Gamma_Z^{inv}), and we find that the present experimental value on \Gamma_Z^{inv}, can be used to place an upper bound on the Z-Z' mixing angle that is consistent with limits obtained previously from other low-energy observables. In this model the charged fermions that correspond to the standard model (SM) mix with its mirror counterparts. This mixing, simultaneously with the Z-Z' one, leads to modifications of the \Gamma(Z --> f \bar{f}) decay width. By comparing with LEP data, we obtain bounds on the standard-mirror lepton mixing angles. We also find that the bottom quark mixing parameters can be chosen to fit the experimental values of R_b, and the resulting values for the Z-Z' mixing angle do not agree with previous bounds. However, this disagreement disappears if one takes the more recent ALEPH data.Comment: 7 pages, 2 figures, REVTe

New Higgs signals induced by mirror fermion mixing effects

We study the conditions under which flavor violation arises in scalar-fermion interactions, as a result of the mixing phenomena between the standard model and exotic fermions. Phenomenological consequences are discussed within the specific context of a left-right model where these additional fermions have mirror properties under the new SU(2)_R gauge group. Bounds on the parameters of the model are obtained from LFV processes; these results are then used to study the LFV Higgs decays (H --> tau l_j, l_j = e, mu), which reach branching ratios that could be detected at future colliders.Comment: 12 pages, 2 figures, ReVTex4, graphicx, to be published in Phys. Rev.

Lepton mass generation and family number violation mechanism in the SU(6)⊗U(1)SU(6)\otimes U(1) model

Lepton family number violation processes arise in the $SU(6)_L \otimes U(1)_Y$ model due to the presence of an extra neutral gauge boson, Z$'$, with family changing couplings, and due to the fact that this model demands the existence of heavy exotic leptons. The mixing of the standard Z with Z$'$ and the mixing of ordinary leptons with exotic ones induce together family changing couplings on the Z and therefore nonvanishing rates for lepton family number violation processes, such as $Z \to e \bar{\mu}$, $\mu \to ee\bar{e}$ and $\mu \to e\gamma$. Additional contributions to the processes $\mu \to e \gamma$ and $\mu \to ee \bar{e}$ are induced from the mass generation mechanism. This last type of contributions may compete with the above one, depending on the masses of the scalars which participate in the diagrams which generate radiatively the masses of the charged leptons. Using the experimental data we compute some bounds for the mixings parameters and for the masses of the scalars.Comment: 12 pages, Latex, 7 figures. Accepted for publication in Int. Journ. of Mod. Phys.

Bounding the Hubble flow in terms of the w parameter

The last decade has seen increasing efforts to circumscribe and bound the cosmological Hubble flow in terms of model-independent constraints on the cosmological fluid - such as, for instance, the classical energy conditions of general relativity. Quite a bit can certainly be said in this regard, but much more refined bounds can be obtained by placing more precise constraints (either theoretical or observational) on the cosmological fluid. In particular, the use of the w-parameter (w=p/rho) has become increasingly common as a surrogate for trying to say something about the cosmological equation of state. Herein we explore the extent to which a constraint on the w-parameter leads to useful and nontrivial constraints on the Hubble flow, in terms of constraints on density rho(z), Hubble parameter H(z), density parameter Omega(z), cosmological distances d(z), and lookback time T(z). In contrast to other partial results in the literature, we carry out the computations for arbitrary values of the space curvature k in [-1,0,+1], equivalently for arbitrary Omega_0 <= 1.Comment: 15 page

Production of neutral scalar Higgs bosons at eγe\gamma colliders

We study the production of neutral scalar (CP even) Higgs bosons in the process $e\gamma\to e h$ by including supersymmetric corrections to the dominant $t$-channel photon exchange amplitude. In addition to the standard model $W^{\pm}$ and fermion loops, there are substantial contributions from chargino loops. For some cases, these contributions can exceed those of the $W$'s and ordinary fermions. The cross sections in this channel are generally one or two orders of magnitude larger than those in the related channel $e\bar{e}\to\gamma h$.Comment: 12 pages RevTeX, 5 postscript figures included, uses epsf.st

Production of the neutral toppion at the e gamma colliders

In the framework of topcolor-assisted technicolor(TC2) model, we study a neutral toppion production process $e^{-}\gamma\to e^{-}\Pi^{0}_{t}$ in this paper. Our results show that the production cross section of $e^{-}\gamma\to e^{-}\Pi^{0}_{t}$ can reach the level of several tens fb, and over $10^{3}$ neutral toppion events can be produced in the planned $e^+e^-$ linear colliders each year. Therefore, such a toppion production process provides us a unique chance to detect toppion events and test the TC2 model. On the other hand, the cross section of $e^{-}\gamma\to e^{-}\Pi^{0}_{t}$ is about one order of magnitude larger than those of some similar processes in SM and MSSM(i.e., $e^{-}\gamma\to e^{-}H$ in SM and $e^{-}\gamma\to e^{-}H^{0}(A^0,h^0)$ in MSSM). So, we can easily distinguish the neutral toppion from other neutral Higgs bosons in SM and MSSM.Comment: 12 pages, 4 figures, The paper has been accepted by Phys.Rev.

Associated production of H^{\pm} and W^{\mp} in high-energy e+e- collisions in the Minimal Supersymmetric Standard Model

We study the associated production of the charged Higgs boson and W^{\pm} gauge boson in high energy e+e- collisions in the Minimal Supersymmetric Standard Model (MSSM). This associated production, which first arises at the one loop level, offers the possibility of producing the charged Higgs boson at the e+e- collider with mass more than half the center-of-mass energy, when the charged Higgs pair production is kinematically forbidden. We present analytic and numerical results for the cross section for e+e- --> W+ H- in the full MSSM, taking into account the previously uncalculated contributions from supersymmetric (SUSY) particles. We find that the contributions of the SUSY particles enhance the cross section over most of SUSY parameter space, especially when the SUSY particles are light, ~200 GeV. With favorable SUSY parameters, at small tan beta, this process can yield more than ten W^{\pm}H^{\mp} events for m_{H^{\pm}} <~ 350 GeV in 500 fb-1 at a 500 GeV e+e- collider, or m_{H^{\pm}} <~ 600 GeV in 1000 fb-1 at a 1000 GeV collider. 80% left-handed polarization of the e- beam improves these reaches to m_{H^{\pm}} <~ 375 GeV and m_{H^{\pm}} <~ 670 GeV, respectively.Comment: v2: 21 pages, 9 figures, comments on Higgs search bounds and new references added, and minor changes; v3: 23 pages, 11 figures, review of literature moved from introduction to new Sec.5 and 2 plots added, references added, typos corrected; v4: bug fixed in nu nubar H0 cross section (Fig.11), version to appear in PR

Clinical indications for digital imaging in dento-alveolar trauma. Part 1: traumatic injuries

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73819/1/j.1600-9657.2006.00509.x.pd