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Duane A. Dicus

Publications and source records attributed to Duane A. Dicus.

At least 19 recordsLinked to original sources
arXiv2019

Vacuum polarization corrections to the $n=2$ and $n=3$ levels in muonic $^4$He

The $n=2$ and $n=3$ levels for muonic Helium are calculated using a potential that includes all one-loop and recoil effects. Electronic vacuum polarization corrections are calculated using an extension of Kinoshita and Nio method. For $n=2$, the results are $2p_{1/2}-2s_{1/2}=1375.05\pm 1.4$ meV and $2p_{3/2}-2s_{1/2}=1521.65\pm 1.4$ meV, essentially in agreement with the latest summary of the current calculations. The $n=3$ results are summarized in tabular form and give $3p_{1/2}-3s_{1/2}=394.76\pm 0.43$ meV and $3d_{3/2}-3p_{3/2}=111.40$ meV.

hep-ph↗
arXiv2018

Muonic hydrogen and the proton size

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 $α^5$. 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 point-like 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 $r_p=\sqrt{\langle r^2\rangle}$. 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.

hep-ph↗
arXiv2015

Interference effects and the use of Higgs boson pair production to study the Higgs trilinear self coupling

We show that the dominant channel proposed for the determination of the Higgs boson trilinear coupling, $pp\to HH+X$ via gluon fusion, exhibits an interference structure that is independent of the collider energy for collider energies in the range $8\,{\rm TeV}\leq \sqrt{s}\leq 100\,{\rm TeV}$ 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.

hep-ph↗
arXiv2014

Residual Symmetries Applied to Neutrino Oscillations at NO$ν$A and T2K

The results previously obtained from the model-independent application of a generalized hidden horizontal $\mathbb{Z}_2$ symmetry to the neutrino mass matrix are updated using the latest global fits for the neutrino oscillation parameters. The resulting prediction for the Dirac $CP$ phase $δ_D$ is in agreement with recent results from T2K. The distribution for the Jarlskog invariant $J_ν$ has become sharper and appears to be approaching a particular region. The approximate effects of matter on long baseline neutrino experiments are explored, and it is shown how the weak interactions between the neutrinos and the particles that make up the Earth can help to determine the mass hierarchy. A similar strategy is employed to show how NO$ν$A and T2K could determine the octant of $θ_a (\equiv θ_{23})$. Finally, the exact effects of matter are obtained numerically in order to make comparisons with the form of the approximate solutions. From this analysis there emerges some interesting features of the effective mass eigenvalues.

hep-ph↗
arXiv2014

Dalitz Decay $H\to\,f\bar{f}γ$ as a Background for $H\toγ\,γ$

The Dalitz decay $H\to\,f\bar{f}γ$ is calculated for very small $f\bar{f}$ invariant masses where the $f\bar{f}$ pair could be mistaken for a photon in analysis of $H\toγγ$ decays. Using the ATLAS cuts and the full Dalitz decay amplitude, we estimate this fraction to be 7.06%.

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arXiv2013

Comparison of $H\to\ell\bar{\ell}γ$ and $H\toγ\,Z, Z\to\ell\bar{\ell}$ including the ATLAS cuts

A precise comparison is made between the Dalitz decay $H\to\ell\bar{\ell}γ$ and the two body decay $H\toγZ,Z\to\ell\bar{\ell}$ for electrons and for muons including experimental cuts appropriate for the ATLAS detector. The widths for these two processes differ by 8% for electrons and 3% for muons. Given that there remain QCD radiative corrections of this order that are not included, this suggests that the isolation of the Dalitz decay will be challenging.

hep-ph↗
arXiv2012

Search for spin-3/2 quarks at the Large Hadron Collider

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.

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arXiv2011

Residual Symmetries for Neutrino Mixing with a Large theta_13 and Nearly Maximal delta_D

The residual Z^s_2(k) and bar Z^s_2(k) symmetries induce a direct and unique phenomenological relation with theta_x (= theta_13) expressed in terms of the other two mixing angles, theta_s (= theta_12) and theta_a (= theta_23), and the Dirac CP phase delta_D. Z^s_2(k) predicts a theta_x probability distribution centered around 3^o ~ 6^o with an uncertainty of 2^o to 4^o while those from bar Z^s_2(k) are approximately a factor of two 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^o (+-106^o) for Z^s_2(k) or +-123^o (+-57^o) for bar Z^s_2(k) which is consistent with the latest global fit. We also give a distribution for the leptonic Jarslkog invariant J_v which can provide further tests from measurements at T2K and NOvA.

hep-ph↗
arXiv2011

Z_2 Symmetry Prediction for the Leptonic Dirac CP Phase

Model-independent consequences of applying a generalized hidden horizontal Z_2 symmetry to the neutrino mass matrix are explored. The Dirac CP phase delta_D can be expressed in terms of the three mixing angles as 4 c_a s_a c_s s_s s_x cos delta_D = (s^2_s - c^2_s s^2_x) (c^2_a - s^2_a) where the s_i, c_i are sines and cosines of the atmospheric, solar, and reactor angles. This relation is independent of neutrino masses and whether neutrinos are Dirac- or Majorana-type. Given the present constraints on the angles, delta_D is constrained to be almost maximal, a result which can be explored in experiments such as NOvA and T2K. The Majorana CP phases do not receive any constraint and are thus model-dependent. Also a distribution of theta_x with a lower limit is obtained without specifying delta_D.

hep-ph↗
arXiv2011

Searching for Colorons at the Large Hadron Collider

We investigate the prospects for the discovery of massive color-octet vector bosons at the CERN Large Hadron Collider with $\sqrt{s} = 14$ TeV. A phenomenological Lagrangian is adopted to evaluate the cross section of a pair of colored vector bosons (colorons, $\tildeρ$) decaying into four colored scalar resonances (hyper-pions, $\tildeπ$), 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 $\tildeπ$ and $\tildeρ$ where discovery is possible. For example, we find that a 5$σ$ signal can be established for $M_{\tildeπ} \alt 495$ GeV ($M_{\tildeρ} \alt 1650$ GeV). More generally we give the reach of this process for a selection of possible cuts and integrated luminosities.

hep-ph↗
arXiv2011

Generalized Hidden $\mathcal{Z}_2$ Symmetry of Neutrino Mixing

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.

hep-ph↗
arXiv2010

Discovering Colorons at the Early Stage LHC

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, $\tildeρ$) decaying into four colored scalar resonances (hyper-pion, $\tildeπ$), 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 $5σ$ signal for $m_{\tildeπ} \alt 220$ GeV or $m_{\tildeρ} \alt 733$ GeV.

hep-ph↗
arXiv2010

Neutrino mixing with broken $S_3$ 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.

hep-ph↗
arXiv2009

Muon decay in a linearly polarized laser field

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.

hep-ph↗
arXiv2008

Muon decay in a laser field

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.

hep-ph↗