We reexamine the structure of the n = 2 levels of muonic hydrogen using a two-body potential that includes all relativistic, recoil and one-loop corrections. The potential was originally derived from QED to describe the muonium atom and accounts for all contributions to order alpha(5). Since one-loop corrections are included, the anomalous magnetic moment contributions of the muon can be identified and replaced by the proton anomalous magnetic moment to describe muonic hydrogen with a pointlike proton. This serves as a convenient starting point to include the dominant electron vacuum polarization corrections to the spectrum and extract the proton's mean squared radius r(p) = root < r(2)>. Our results are consistent with other theoretical calculations that find that the muonic hydrogen value for r(p) is smaller than the result obtained from electron scattering.

To gain some sense about the likelihood of measuring the Higgs boson quartic coupling, we calculate the contribution to the triple Higgs production cross section from the subprocesses $q\overline{q}\ensuremath{\rightarrow}ZHHH$ and $q{\overline{q}}^{\ensuremath{'}}\ensuremath{\rightarrow}WHHH$. Our results illustrate that determining this coupling, or even providing experimental evidence that it exists, will be very difficult.

We show that the dominant channel proposed for the determination of the Higgs boson trilinear coupling, pp -> HH + X via gluon fusion, exhibits an interference structure that is independent of the collider energy for collider energies in the range 8 TeV <= root s <= = 100 TeV and is almost maximally destructive. This insensitivity to the collider energy remains approximately true for a variety of other two Higgs production mechanisms although the magnitude of the interference varies widely.

We revisit an earlier calculation of the decay H -> e (e) over bar gamma using the recently reported mass value of the Higgs boson candidate observed in the ATLAS and CMS experiments together with cuts that are appropriate for experimental analyses. DOI: 10.1103/PhysRevD.87.077301

We consider the pair production of color triplet spin-3/2 quarks and their subsequent decays at the LHC. This particle, if produced, will most likely decay into top quark and gluon, bottom quark and gluon, or a light quark jet and gluon, depending on the quantum number of the spin-3/2 particle. This would lead to signals with ttbar+jj, bbbar+jj, or 4j in the final states. We present a detailed analysis of the signals and backgrounds at sqrt{s}= 7, 8 and 14 TeV and show the reach for such particles by solving for observable mass values for the spin-3/2 quarks through its decay products.

The residual Z(2)(s()k) and (Z) over bar (s)(2)(k) symmetries induce a direct and unique phenomenological relation with theta(x)(equivalent to theta(13)) expressed in terms of the other two mixing angles theta(s)(equivalent to theta(12)) and theta(a) (equivalent to theta(23)) and the Dirac CP phase delta(D). Z(2)(s()k) predicts a theta(x) probability distribution centered around 3 degrees-6 degrees with an uncertainty of 2 degrees-4 degrees, while those from (Z) over bar (s)(2)(k) are approximately a factor of 2 larger. Either result fits the T2K, MINOS, and Double Chooz measurements. Alternately, a prediction for the Dirac CP phase delta(D) results in a peak at +/- 74 degrees (+/- 106 degrees) for Z(2)(s()k) or +/- 123 degrees (+/- 57 degrees) for (Z) over bar (s)(2)(k) which is consistent with the latest global fit. We also give a distribution for the leptonic Jarlskog invariant J(nu) which can provide further tests from measurements at T2K and NO nu A.

The effective interaction for two neutrino-two photon coupling is used to find an approximate width for the decay of the Z boson into the nu(nu) over bar gamma gamma final state.

We investigate the prospects for the discovery of massive hyper-gluons using data from the early runs of the CERN Large Hadron Collider with $\sqrt{s} = 7$ TeV and assuming an integrated luminosity of 1 fb$^{-1}$. A phenomenological Lagrangian is adopted to evaluate the cross section of a pair of colored vector bosons (coloron, $\tilde{\rho}$) decaying into four colored scalar resonances (hyper-pion, $\tilde{\pi}$), which then decay into eight gluons. We include the dominant physics background from the production of $8g$, $7g1q$, $6g2q$, and $5g3q$. We find an abundance of signal events and that realistic cuts reduce the background enough to establish a $5\sigma$ signal for $m_{\tilde{\pi}} \alt 220$ GeV or $m_{\tilde{\rho}} \alt 733$ GeV.

We explore the consequences of the neutrino mass matrix having a hidden Z(2) symmetry and one zero eigenvalue. When implemented, these two conditions give relations among the mixing angles. In addition, fitting these relations to the existing oscillation data allows limits to be placed on the parameter of the symmetry.

We investigate the prospects for the discovery of massive color-octet vector bosons at the CERN Large Hadron Collider with root s = 14 TeV. A phenomenological Lagrangian is adopted to evaluate the cross section of a pair of colored vector bosons (colorons, (rho) over tilde) decaying into four colored scalar resonances (hyper-pions, (pi) over tilde), which then decay into eight gluons. We include the dominant physics background from the production of 8g, 7g1q, 6g2q, and 5g3q, and determine the masses of (pi) over tilde and (rho) over tilde where discovery is possible. For example, we find that a 5 sigma signal can be established for M-(pi) over tilde less than or similar to 495 GeV (M-(rho) over bar less than or similar to 1650 GeV). More generally we give the reach of this process for a selection of possible cuts and integrated luminosities.

We explore the consequences of the neutrino mass matrix having a hidden $\mathcal{Z}_2$ symmetry and one zero eigenvalue. When implemented, these two conditions give relations among the mixing angles. In addition, fitting these relations to the existing oscillation data allows limits to be placed on the parameter of the symmetry.

We explore the consequences of assuming that the neutrino mass matrix is a linear combination of the matrices of a three-dimensional representation of the group S-3 and that it has one zero mass eigenvalue. When implemented, these two assumptions allow us to express the transformation matrix relating the mass eigenstates to the flavor eigenstates in terms of a single parameter which we fit to the available data.

In a previous paper, we showed that the decay rate of a muon is only slightly affected by the presence of a circularly polarized laser and we gave an analytic expression for the correction. In this paper, we present the analytical result for the case of a linearly polarized laser. Again the effect of the laser is small.

We investigate the change in the decay rate of a muon caused by embedding it in the field of a laser. A previous paper found that the change could be large, as much as an order of magnitude. We find the more intuitive result that the change is small and give analytic expressions for the small corrections.

We investigate the behavior of the critical charge for spontaneous pair production, Z(C), defined as the charge at which the total energy of a K-shell electron is E = -m(e), as a function of the radius R of the charge distribution. Our approach is to solve the Dirac equation for a potential V(r) consisting of a spherically symmetrical charge distribution of radius R and a Coulomb tail. For a spherical shell distribution of the type usually associated with color-flavor locked strange quark nuggets, we confirm the relation Z(C) = 0.71R (fm) for sufficiently large R obtained by Madsen, who used an approach based on the Thomas-Fermi model. We also present results for a uniformly charged sphere and again find that Z(C) similar to R for large enough R. Also discussed is the behavior of Z(C) when simple ad hoc modifications are made to the potential for 0 <= r < R.

We present a detailed calculation of the electron-positron production rate using neutrinos in an intense background magnetic field. The computation is done for the process $\ensuremath{\nu}\ensuremath{\rightarrow}\ensuremath{\nu}e\overline{e}$ (where $\ensuremath{\nu}$ can be ${\ensuremath{\nu}}_{e}$, ${\ensuremath{\nu}}_{\ensuremath{\mu}}$, or ${\ensuremath{\nu}}_{\ensuremath{\tau}}$) within the framework of the standard model. Results are given for various combinations of Landau levels over a range of possible incoming neutrino energies and magnetic field strengths.

We investigate a top-down approach for modeling the dark energy where we fit the luminosity distances directly rather than indirectly fitting the equation of state.

We utilize the recently released supernova data of Riess et al. on the acceleration of the universe to determine how the parameters of a particular modification of gravity, the DGP 5-dimensional theory, are changed when compared to determinations using earlier data sets. We show the parameters of the theory are now very tightly constrained and at very reasonable values. For example, the curvature parameter, Ω_k, in contrast to an earlier analysis which used a smaller data set, is now consistent with zero, and the redshift at which the universe starts to accelerate is near unity.

We investigate the prospects for the discovery at the CERN Large Hadron Collider (LHC) of a neutral Higgs boson produced with one bottom quark followed by Higgs decay into a muon pair. We work within the framework of the minimal supersymmetric model. The dominant physics background from the production of b mu(+)mu(-), j mu(+)mu(-), j=g,u,d,s,c, and bbW+W- is calculated with realistic acceptance cuts. Promising results are found for the CP-odd pseudoscalar (A0) and the heavier CP-even scalar (H0) Higgs bosons with masses up to 600 GeV. This discovery channel with one energetic bottom quark greatly improves the discovery potential of the LHC beyond the inclusive channel pp-->phi(0)-->mu(+)mu(-)+X.