On the Hadronic Contribution to Light-by-light Scattering in gμ−2g_\mu-2

We comment on the theoretical uncertainties involved in estimating the hadronic effects on the light-by-light scattering contribution to the anomalous magnetic moment of the muon, especially based on the analysis and results of T. Kinoshita, B. Ni\v zi\'c, and Y. Okamoto, Phys.\ Rev.\ D31, 2108 (1985). From the point of view of an effective field theory and chiral perturbation theory, we suggest that the charged pion contribution may be better determined than has been appreciated. However, the neutral pion contribution needs greater theoretical insight before its magnitude can be reliably estimated.Comment: 9 pages, no figures, U. Michigan UM-TH-93-18. (Input phyzzm to compile.) Revised version has minor changes in text. To be published in Phys. Rev. D, Comments sectio

Treatment of sleep apnea in chronic heart failure patients with auto-servo ventilation improves sleep fragmentation: a randomized controlled trial

Background: Impaired sleep efficiency is independently associated with worse prognosis in patients with chronic heart failure (CHF). Therefore, a test was conducted on whether auto-servo ventilation (ASV, biphasic positive airway pressure [BiPAP]-ASV, Philips Respironics) reduces sleep fragmentation and improves sleep efficiency in CHF patients with central sleep apnea (CSA) or obstructive sleep apnea (OSA). Methods: In this multicenter, randomized, parallel group trial, a study was conducted on 63 CHF patients (age 64 +/- 10 years; left ventricular ejection fraction 29 +/- 7%) with CSA or OSA (apnea-hypopnea Index, AHI 47 +/- 18/h; 46% CSA) referred to sleep laboratories of the four participating centers. Participants were randomized to either ASV (n = 32) or optimal medical treatment alone (control, n = 31). Results: Polysomnography (PSG) and actigraphy at home (home) with centralized blinded scoring were obtained at baseline and 12 weeks. ASV significantly reduced sleep fragmentation (total arousal indexpsc: -16.4 +/- 20.6 vs.-0.6 13.2/h, p = 0.001; sleep fragmentation index(home):-7.6 +/- 15.6 versus 4.3 +/- 13.9/h, p = 0.003, respectively) and significantly increased sleep efficiency assessed by actigraphy (SEhome) compared to controls (2.3 +/- 10.1 vs.-2.1 +/- 6.9%, p = 0.002). Effects of ASV on sleep fragmentation and efficiency were similar in patients suffering from OSA and CSA. Conclusions: At home, ASV treatment modestly improves sleep fragmentation as well as sleep efficiency in CHF patients having either CSA or OSA. (C) 2015 Elsevier B.V. All rights reserved

CP violation in gauge theories

We define the CP transformation properties of scalars, fermions and vectors in a gauge theory and show that only three types of interactions can lead to CP violation: scalar interactions, fermion-scalar interactions and $F \tilde F$ associated with the strong CP problem and which involve only the gauge fields. For technicolor theories this implies the absence of CP violation within perturbation theory.Comment: 5 pages, 1 figure, revtex and epsf require

Dimension-Six Terms in the Standard Model Lagrangian

When the Standard Model is considered as an effective low-energy theory, higher dimensional interaction terms appear in the Lagrangian. Dimension-six terms have been enumerated in the classical article by Buchmueller and Wyler [3]. Although redundance of some of those operators has been already noted in the literature, no updated complete list has been published to date. Here we perform their classification once again from the outset. Assuming baryon number conservation, we find 15 + 19 + 25 = 59 independent operators (barring flavour structure and Hermitian conjugations), as compared to 16 + 35 + 29 = 80 in Ref.[3]. The three summed numbers refer to operators containing 0, 2 and 4 fermion fields. If the assumption of baryon number conservation is relaxed, 4 new operators arise in the four-fermion sector.Comment: 16 pages, no figures, v3: Redundant B-violating operator remove

Four-Fermi Effective Operators in Top-Quark Production and Decay

Effects of four-Fermi-type new interactions are studied in top-quark pair production and their subsequent decays at future e^+e^- colliders. Secondary-lepton-energy distributions are calculated for arbitrary longitudinal beam polarizations. An optimal-observables procedure is applied for the determination of new parameters.Comment: Polarized e^- plus unpolarized e^+ collisions were include

Muon Anomalous Magnetic Moment and Lepton Flavor Violation

A non-universal interaction, which involves only the third family leptons induces lepton flavor violating couplings and contributes to the anomalous magnetic moment of muon. In this paper, we study the effects of non-universal interaction on muon (g-2) and rare decay $\tau \to \mu \gamma$ by using an effective lagrangian technique, and a phenomenological $Z^\prime$ model where $Z^\prime$ couples only to the third family lepton. We find that the deviation from the theory can be explained and the induced $\tau \to \mu \gamma$ rate could be very close to the current experimental limit. In the $Z^\prime$ model, $M_{Z^\prime}$ has to be lighter than 2.6 TeV.Comment: references added, the version to appear in PR

A Perturbative Calculation of the Electromagnetic Form Factors of the Deuteron

Making use of the effective field theory expansion recently developed by the authors, we compute the electromagnetic form factors of the deuteron analytically to next-to-leading order (NLO). The computation is rather simple, and involves calculating several Feynman diagrams, using dimensional regularization. The results agree well with data and indicate that the expansion is converging. They do not suffer from any ambiguities arising from off-shell versus on-shell amplitudes.Comment: 22 pages, 8 figures. Discussion of effective range theory added, typos correcte

Sensitivity to anomalous quartic gauge couplings in photon-photon interactions at the LHC

The exclusive two-photon production at the LHC of pairs of W and Z bosons provides a novel and unique test-ground for the electroweak gauge boson sector. In particular it offers, thanks to high gamma-gamma center-of-mass energies, large and direct sensitivity to the anomalous quartic gauge couplings otherwise very difficult to investigate at the LHC. An initial analysis has been performed assuming leptonic decays and generic acceptance cuts. Simulation of a simple counting experiment has shown for the integrated luminosity of 10 fb-1 at least four thousand times larger sensitivity to the genuine quartic couplings, a_0^W, a_0^Z, a_C^W and a_C^Z, than those obtained at LEP. The impact of the unitarity constraints on the estimated limits has been studied using the dipole form-factors. Finally, differential distributions of the decay leptons have been provided to illustrate the potential for further improvements of the sensitivities.Comment: 8 pages and 11 figures, Contribution to the CERN workshop on "High energy photon collisions at the LHC", 22-25 April 200

Effective Theory of a Dynamically Broken Electroweak Standard Model at NLO

We consider the Standard Model as an effective theory at the weak scale $v$ of a generic new strong interaction that dynamically breaks electroweak symmetry at the energy scale $\Lambda\sim$ (few) TeV. Assuming only the minimal field content with the Standard Model fermions and gauge bosons, but without a light Higgs particle, we construct the complete Lagrangian through next-to-leading order, that is, including terms of order $v^2/\Lambda^2$. The systematics behind this expansion is clarified. Although similar to chiral perturbation theory, it is not governed by the dimension of operators alone, but depends in an essential way on the loop expansion. Power-counting formulas are derived that indicate the classes of operators required at the next-to-leading order. The complete set of operators at leading and next-to-leading order is then listed, based on the restrictions implied by the Standard-Model gauge symmetries. We recover the well-known operators discussed in the literature in connection with the electroweak chiral Lagrangian and in similar contexts, but we collect a complete and systematic list of all terms through order $v^2/\Lambda^2$. This includes some operators not discussed in explicit terms before. We also show that a few of the previously considered operators can be eliminated via the equations of motion. As another important result we confirm the known list of dimension-6 operators in the Standard Model with an elementary Higgs doublet, essentially as a special case of our scenario.Comment: 35 pages, 1 figure; references adde

Testing new physics/couplings at the NLC (Talk prsented in The 5th Topical Seminar on ``The irresistible rise of the Standard Model'', San Miniato al Todesco, Italy, April 21-25 1997)

I present a brief overview of the advantages of using a consistent effective Lagrangian approach in parameterizing virtual new physics effects. I then apply the formalism to certain top-quark processes.Comment: 7 pages, 5 figures. Requires epsf.st