An irreducible massive superspin one half action built from the chiral dotted spinor superfield

Although the chiral dotted spinor superfield should describe a Massive Superspin One Half multiplet, it has not been obvious how to derive this from an action. In this paper this is done by including a chiral undotted spinor superfield, finding the BRST transformations that govern both of these, and then finding the action as an invariant of the transformations. It turns out that both kinds of spinor superfields are needed. Moreover, the BRST transformations for the two kinds of chiral spinor superfields are generated from each other by a special involution that exchanges Grassmann odd (even) sources with Grassmann even (odd) fields

An extraordinary mass invariant and an obstruction in a massive superspin one half model made with a chiral dotted spinor superfield

An action for a complex irreducible massive superspin 12 multiplet can be constructed out of two chiral dotted spinor and two chiral undotted spinor superfields. To make this action a sensible one, additional ‘reality constraints’ are needed, and the notion of BRST recycling is needed to find the supersymmetry transformations of the theory with these additional constraints. This theory possesses three possible mass terms. An earlier paper examined the theory with the first mass term. This paper adds a second mass term and examines the consequences of that. This second mass invariant is ‘extraordinary’, which means that it is intrinsically dependent on the Zinn sources (‘antifields’) of the theory. This in turn implies that the action needs to be ‘completed’ so that it yields zero for the relevant Poisson Bracket. This ‘Completion’ meets an ‘Obstruction’, which is a ghost charge one object in the BRST cohomology space. Usually Obstructions arise from a one loop calculation, in which case they form anomalies of the theory. However this Obstruction arises at tree level from the completion. The coefficient of the Obstruction needs to be set to zero. This restores the complex irreducible massive superspin 12 multiplet to its usual structure, except that the mass is constructed out of the two mass parameters. The construction suggests interesting possibilities for related interacting theories

ALP conversion and the soft X-ray excess in the outskirts of the Coma cluster

It was recently found that the soft X-ray excess in the center of the Coma cluster can be fitted by conversion of axion-like-particles (ALPs) of a cosmic axion background (CAB) to photons. We extend this analysis to the outskirts of Coma, including regions up to 5 Mpc from the center of the cluster. We extract the excess soft X-ray flux from ROSAT All-Sky Survey data and compare it to the expected flux from ALP to photon conversion of a CAB. The soft X-ray excess both in the center and the outskirts of Coma can be simultaneously fitted by ALP to photon conversion of a CAB. Given the uncertainties of the cluster magnetic field in the outskirts we constrain the parameter space of the CAB. In particular, an upper limit on the CAB mean energy and a range of allowed ALP-photon couplings are derived

3.55 keV photon lines from axion to photon conversion in the Milky Way and M31

We further explore a scenario in which the recently observed 3.55 keV photon line arises from dark matter decay to an axion-like particle (ALP) of energy 3.55 keV, which then converts to a photon in astrophysical magnetic fields. This ALP scenario is well-motivated by the observed morphology of the 3.55 keV flux. For this scenario we study the expected flux from dark matter decay in the galactic halos of both the Milky Way and Andromeda (M31). The Milky Way magnetic field is asymmetric about the galactic centre, and so the resulting 3.55 keV flux morphology differs significantly from the case of direct dark matter decay to photons. However the Milky Way magnetic field is not large enough to generate an observable signal, even with ASTRO-H. In contrast, M31 has optimal conditions for a → γ conversion and the intrinsic signal from M31 becomes two orders of magnitude larger than for the Milky Way, comparable to that from clusters and consistent with observations

The darkness of spin-0 dark radiation

We show that the scattering of a general spin-0 sector of dark radiation off the pre-recombination thermal plasma results in undetectably small spectral distortions of the Cosmic Microwave Background

An explicit Z ′ -boson explanation of the B → K ∗ μ + μ − anomaly

A global fit to the recent B → K ∗ μ + μ − data shows indications for a large new-physics contribution to the Wilson coefficient of the semi-leptonic vector operator. In this article we consider a simple Z ′ -boson model of 3-3-1 type that can accommodate such an effect without violating any other constraint from quark-flavour physics. Implications for yet unobserved decay modes such as B → X s ν $\overline{v}$ and longstanding puzzles like B → πK are also discussed. The Z ′ -boson masses required to address the observed anomaly lie in the range of 7 TeV. Such heavy Z ′ bosons evade the existing bounds from precision data and direct searches, and will remain difficult to discover even at a high-luminosity LHC. The potential of an ILC as well as the next generation of low-energy parity-violation experiments in constraining the Z ′ -boson parameter space is also examined

Ultra-weak sector, Higgs boson mass, and the dilaton

The Higgs boson mass may arise from a portal coupling to a singlet field σ which has a very large VEV f≫mHiggs . This requires a sector of “ultra-weak” couplings ζi where ζi≲mHiggs2/f2 . Ultra-weak couplings are technically naturally small due to a custodial shift symmetry of σ in the ζi→0 limit. The singlet field σ has properties similar to a pseudo-dilaton. We engineer explicit breaking of scale invariance in the ultra-weak sector via a Coleman–Weinberg potential, which requires hierarchies amongst the ultra-weak couplings

An ultra-weak sector, the strong CP problem and the pseudo-Goldstone dilaton

In the context of a Coleman–Weinberg mechanism for the Higgs boson mass, we address the strong CP problem. We show that a DFSZ-like invisible axion model with a gauge-singlet complex scalar field S , whose couplings to the Standard Model are naturally ultra-weak, can solve the strong CP problem and simultaneously generate acceptable electroweak symmetry breaking. The ultra-weak couplings of the singlet S are associated with underlying approximate shift symmetries that act as custodial symmetries and maintain technical naturalness. The model also contains a very light pseudo-Goldstone dilaton that is consistent with cosmological Polonyi bounds, and the axion can be the dark matter of the universe. We further outline how a SUSY version of this model, which may be required in the context of Grand Unification, can avoid introducing a hierarchy problem

Searching for t → c ( u ) h with dipole moments

A discovery of flavour-changing Higgs-boson decays would constitute an undeniable signal of new physics. We derive model-independent constraints on the tch and tuh couplings that arise from the bounds on hadronic electric dipole moments. Comparisons of the present and future sensitivities with both the direct LHC constraints and the indirect limits from D -meson physics are also presented

New determination of the D0→K−π+π0 and D0→K−π+π+π− coherence factors and average strong-phase differences

Measurements of the coherence factors ( RKππ0 and RK3π ) and the average strong-phase differences ( δKππ0D and δK3πD ) for the decays D0→K−π+π0 and D0→K−π+π+π− are presented. These parameters are important inputs to the determination of the unitarity triangle angle γ in B∓→DK∓ decays, where D designates a D0 or D¯0 meson decaying to a common final state. The measurements are made using quantum correlated DD¯ decays collected by the CLEO-c experiment at the ψ(3770) resonance, and augment a previously published analysis by the inclusion of new events in which the signal decay is tagged by the mode D→K0Sπ+π− . The measurements also benefit from improved knowledge of external inputs, namely the D0D¯0 mixing parameters, rKπD and several D -meson branching fractions. The measured values are RKππ0=0.82±0.07 , δKππ0D=(164+20−14)° , RK3π=0.32+0.20−0.28 and δK3πD=(225+21−78)° . Consideration is given to how these measurements can be improved further by using the larger quantum-correlated data set collected by BESIII