Vacuum Stability, Perturbativity, and Scalar Singlet Dark Matter

We analyze the one-loop vacuum stability and perturbativity bounds on a singlet extension of the Standard Model (SM) scalar sector containing a scalar dark matter candidate. We show that the presence of the singlet-doublet quartic interaction relaxes the vacuum stability lower bound on the SM Higgs mass as a function of the cutoff and lowers the corresponding upper bound based on perturbativity considerations. We also find that vacuum stability requirements may place a lower bound on the singlet dark matter mass for given singlet quartic self coupling, leading to restrictions on the parameter space consistent with the observed relic density. We argue that discovery of a light singlet scalar dark matter particle could provide indirect information on the singlet quartic self-coupling.Comment: 25 pages, 10 figures; v2 - fixed minor typos; v3 - added to text discussions of other references, changed coloring of figures for easier black and white viewin

Neutrinos

229 pages229 pages229 pagesThe Proceedings of the 2011 workshop on Fundamental Physics at the Intensity Frontier. Science opportunities at the intensity frontier are identified and described in the areas of heavy quarks, charged leptons, neutrinos, proton decay, new light weakly-coupled particles, and nucleons, nuclei, and atoms

Review of Particle Physics

The Review summarizes much of particle physics and cosmology. Using data from previous editions, plus 2,143 new measurements from 709 papers, we list, evaluate, and average measured properties of gauge bosons and the recently discovered Higgs boson, leptons, quarks, mesons, and baryons. We summarize searches for hypothetical particles such as supersymmetric particles, heavy bosons, axions, dark photons, etc. Particle properties and search limits are listed in Summary Tables. We give numerous tables, figures, formulae, and reviews of topics such as Higgs Boson Physics, Supersymmetry, Grand Unified Theories, Neutrino Mixing, Dark Energy, Dark Matter, Cosmology, Particle Detectors, Colliders, Probability and Statistics. Among the 120 reviews are many that are new or heavily revised, including a new review on Machine Learning, and one on Spectroscopy of Light Meson Resonances. The Review is divided into two volumes. Volume 1 includes the Summary Tables and 97 review articles. Volume 2 consists of the Particle Listings and contains also 23 reviews that address specific aspects of the data presented in the Listings. The complete Review (both volumes) is published online on the website of the Particle Data Group (pdg.lbl.gov) and in a journal. Volume 1 is available in print as the PDG Book. A Particle Physics Booklet with the Summary Tables and essential tables, figures, and equations from selected review articles is available in print, as a web version optimized for use on phones, and as an Android app

Sterile neutrinos in leptonic and semileptonic decays

We address the impact of a modified $W \ell \nu$ coupling on a wide range of observables, such as $\tau$ leptonic and mesonic decays, leptonic decays of pseudoscalar mesons, as well as semileptonic meson decays. In particular, we concentrate on deviations from lepton flavour universality, focusing on the ratios $R_{P} = \Gamma (P \to \ell \nu) / \Gamma (P \to \ell' \nu)$, with $P=K, \pi, D, D_s$, $R(D)={\Gamma (B^+ \to D \tau^+ \nu)}/{\Gamma (B^+ \to D\ell^+ \nu)}$, $R \tau={\Gamma (\tau\to \mu\nu\nu)}/{\Gamma (\tau\to e\nu\nu)}$, $R^{\ell \tau}_P=\Gamma(\tau\to P\nu)/\Gamma(P\to \ell \nu)$, and $\text{BR}(B \to \tau \nu)$. We further consider leptonic gauge boson decays, such as $W\to \ell \nu$ and $Z \to \nu \nu$. For all the above observables, we provide the corresponding complete analytical expressions, derived for the case of massive neutrinos. Working in the framework of the Standard Model extended by additional sterile fermions, which mix with the active (left-handed) neutrinos, we numerically study the impact of active-sterile mixings on the above mentioned observables.Comment: 31 pages, Latex, 22 figures. Published in JHE

Ultrasonic courtship vocalizations in wild house mice: spectrographic analyses

House mice emit ultrasonic vocalizations (USVs) during courtship, which are sexually dimorphic and function to attract mates. Spectrographic analyses of laboratory mice show that USVs are surprisingly complex and have features of song. In this study, we conducted the first spectral and temporal analyses of recordings from wild house mice (F1 from wild-caught Mus musculus musculus ). Inspection of the spectral shape of syllables shows that the USVs from wild mice can be classified by both frequency and duration, and the most apparent distinction is between low- versus high-frequency calls. High-frequency calls of wild mice seem to be emitted at a much higher frequency range than previously found in some laboratory mice. Interestingly, we found that 20% of males do not vocalize at all, though the reason for their behaviour is unclear. Future studies are needed to determine what kind of information is conveyed in these complex vocalizations, and why some males appear to be non-vocalizers