Electric dipole moments (edms) of bound states that arise from the constituents having edms are studied with field-theoretic techniques. The systems treated are the neutron and a set of paramagnetic atoms. In the latter case it is well known that the atomic edm differs greatly from the electron edm when the internal electric fields of the atom are taken into account. In the nonrelativistic limit these fields lead to a complete suppression, but for heavy atoms large enhancement factors are present. A general bound-state field theory approach applicable to both the neutron and paramagnetic atoms is set up. It is applied first to the neutron, treating the quarks as moving freely in a confining spherical well. It is shown that the effect of internal electric fields is small in this case. The atomic problem is then revisited using field-theory techniques in place of the usual Hamiltonian methods, and the atomic enhancement factor is shown to be consistent with previous calculations. Possible application of bound-state techniques to other sources of the neutron edm is discussed.

We study the constraints of crossing symmetry and unitarity in general 3D conformal field theories. In doing so we derive new results for conformal blocks appearing in four-point functions of scalars and present an efficient method for their computation in arbitrary space-time dimension. Comparing the resulting bounds on operator dimensions and product-expansion coefficients in 3D to known results, we find that the 3D Ising model lies at a corner point on the boundary of the allowed parameter space. We also derive general upper bounds on the dimensions of higher spin operators, relevant in the context of theories with weakly broken higher spin symmetries.

We study spherically symmetric solutions in massive gravity generated by matter sources with polytropic equation of state. We concentrate in the nonperturbative regime where the mass term nonlinearities are important, and present the main features of the solutions.

The thermodynamic properties of a static and spherically symmetric hairy black hole solution arising in massive gravity with spontaneous Lorentz breaking are investigated. The analysis is carried out by enclosing the black hole in a spherical cavity whose surface is maintained at a fixed temperature $T$. It turns out that the ensemble is well-defined only if the “hair” parameter $Q$ characterizing the solution is conserved. Under this condition we compute some relevant thermodynamic quantities, such as the thermal energy and entropy, and we study the stability and phase structure of the ensemble. In particular, for negative values of the hair parameter, the phase structure is isomorphic to the one of Reissner-Nordstrom black holes in the canonical ensemble. Moreover, the phase diagram in the plan $(Q,T)$ has a line of first-order phase transition that at a critical value of $Q$ terminates in a second-order phase transition. Below this line the dominant phase consists of small, cold black holes that are long-lived and may thus contribute much more to the energy density of the Universe than what is observationally allowed for radiating black holes.

The Alcock-Paczynski effect uses the fact that, when analyzed with the correct geometry, we should observe structure that is statistically isotropic in the Universe. For structure undergoing cosmological expansion with the background, this constrains the product of the Hubble parameter and the angular diameter distance. However, the expansion of the Universe is inhomogeneous and local curvature depends on density. We argue that this distorts the Alcock-Paczynski effect on small scales. After analyzing the dynamics of galaxy pairs in the Millennium Simulation [9], we find an interplay between peculiar velocities, galaxy properties and local density that affects how pairs trace cosmological expansion. We find that only low-mass, isolated galaxy pairs trace the average expansion with a minimum “correction” for peculiar velocities. Other pairs require larger, more cosmology- and redshift-dependent peculiar velocity corrections and, in the small separation limit of being bound in a collapsed system, do not carry cosmological information.

We show that the current extragalactic gamma-ray background (EGB) measurement below 100 GeV sets an upper limit on EGB itself at very high energy (VHE) above 100 GeV. The limit is conservative for the electromagnetic cascade emission from VHE EGB interacting with the cosmic microwave-to-optical background radiation not to exceed the current EGB measurement. The cascade component fits the measured VHE EGB spectrum rather well. However, once we add the contribution from known source classes, the Fermi VHE EGB observation exceeds or even violates the limit, which is approximated as $E^{2}dN/dE<4.5\times {10}^{-5}(E/100\mathrm{GeV}{)}^{-0.7}\mathrm{MeV}/{\mathrm{cm}}^2/\mathrm{s}/\mathrm{sr}$. The upper limit above 100 GeV is useful in the future to probe the EGB origin and the new physics like axionlike particles and Lorentz-invariance violation.

If dark matter interacts with quarks or gluons, the mediator of these interactions is either directly accessible at the LHC or is so heavy that its effects are encoded in contact operators. We find that the self-consistency of a contact operator description at the LHC implies bounds on the mediator scale stronger than those found from missing energy searches. This translates into spin-independent elastic scattering cross sections at a level $\lesssim {10}^{-41}{\mathrm{cm}}^2$, with direct implications for the DAMA, CoGeNT, and CRESST-II anomalies. We then carefully explore the potential of monojet searches in the light mediator limit, focusing on a $Z^{\prime }$ model with arbitrary couplings to quarks and dark matter. We find that Tevatron data currently provide the most stringent bounds for dark matter and $Z^{\prime }$ masses below 100 GeV, and that these searches can constrain models for the DAMA, CoGeNT, and CRESST-II anomalies only if the mediator can decay to a pair of dark matter particles.

LHC has found hints for a Higgs particle of 125 GeV. We investigate the possibility that such a particle is a mixture of scalar and pseudoscalar states. For definiteness, we concentrate on a two-Higgs doublet model with explicit $CP$ violation and soft $Z_2$ violation. Including all Higgs production mechanisms, we determine the current constraints obtained by comparing $h\to \gamma \gamma$ with $h\to V{V}^{*}$, and comment on the information which can be gained by measurements of $h\to b\overline{b}$. We find bounds $|s_2|\lesssim 0.83$ at one sigma, where $|s_2|=0$ ($|s_2|=1$) corresponds to a pure scalar (pure pseudoscalar) state.

Many models of beyond the standard model physics involve heavy colored fermions. We study models where the new fermions have vector interactions and examine the connection between electroweak precision measurements and Higgs production. In particular, for parameters that are allowed by precision measurements, we show that the gluon fusion Higgs cross section and the Higgs decay branching ratios must be close to those predicted by the standard model. The models we discuss thus represent scenarios with new physics that will be extremely difficult to distinguish from the minimal standard model. We pay particular attention to the decoupling properties of the vector fermions.

We calculate the lattice quark propagator in Coulomb gauge from both dynamical and quenched configurations. We show that in the continuum limit both the static and the full quark propagators are multiplicatively renormalizable. From the propagator we extract the quark renormalization function $Z(|\mathit{p}|)$ and the running mass $M(|\mathit{p}|)$ and extrapolate the latter to the chiral limit. We find that $M(|\mathit{p}|)$ practically coincides with the corresponding Landau gauge function for small momenta. The computation of $M(|\mathit{p}|)$ can, however, be made more efficient in Coulomb gauge; this can lead to a better determination of the chiral mass and the quark anomalous dimension. Moreover from the structure of the full propagator we can read an expression for the dispersion relation of quarks, compatible with an IR divergent effective energy. If confirmed on larger volumes, this finding would allow one to extend the Gribov–Zwanziger confinement mechanism to the fermionic sector of QCD.

Perturbative and nonperturbative results are presented on the renormalization constants of the quark field and the vector, axial-vector, pseudoscalar, scalar, and tensor currents. The perturbative computation, carried out at one-loop level and up to second order in the lattice spacing, is performed for a fermion action, which includes the clover term and the twisted mass parameter yielding results that are applicable for unimproved Wilson fermions, as well as for improved clover and twisted mass fermions. We consider ten variants of the Symanzik improved gauge action corresponding to ten different values of the plaquette coefficients. Nonperturbative results are obtained using the twisted mass Wilson fermion formulation employing two degenerate dynamical quarks and the tree-level Symanzik improved gluon action. The simulations are performed for pion masses in the range of 480–260 MeV and at three values of the lattice spacing, $a$, corresponding to $\beta =3.9$, 4.05, 4.20. For each renormalization factor computed nonperturbatively we subtract its perturbative $\mathcal{O}(a^2)$ terms so that we eliminate part of the cutoff artifacts. The renormalization constants are converted to $\overline{\mathrm{MS}}$ at a scale of $\mu =2\mathrm{GeV}$. The perturbative results depend on a large number of parameters and are made easily accessible to the reader by including them in the distribution package of this paper, as a Mathematica input file.

This biennial Review summarizes much of particle physics. Using data from previous editions, plus 2658 new measurements from 644 papers, we list, evaluate, and average measured properties of gauge bosons, leptons, quarks, mesons, and baryons. We summarize searches for hypothetical particles such as Higgs bosons, heavy neutrinos, and supersymmetric particles. All the particle properties and search limits are listed in Summary Tables. We also give numerous tables, figures, formulae, and reviews of topics such as the Standard Model, particle detectors, probability, and statistics. Among the 112 reviews are many that are new or heavily revised including those on Heavy-Quark and Soft-Collinear Effective Theory, Neutrino Cross Section Measurements, Monte Carlo Event Generators, Lattice QCD, Heavy Quarkonium Spectroscopy, Top Quark, Dark Matter, $V_{\mathit{cb}}$ & $V_{\mathit{ub}}$, Quantum Chromodynamics, High-Energy Collider Parameters, Astrophysical Constants, Cosmological Parameters, and Dark Matter.

A booklet is available containing the Summary Tables and abbreviated versions of some of the other sections of this full Review. All tables, listings, and reviews (and errata) are also available on the Particle Data Group website: http://pdg.lbl.gov/.

The 2012 edition of Review of Particle Physics is published for the Particle Data Group as article 010001 in volume 86 of Physical Review D.

This edition should be cited as: J. Beringer et al. (Particle Data Group), Phys. Rev. D 86, 010001 (2012).

We consider a new large-$N$ limit, in which the ’t Hooft coupling grows with $N$. We argue that a class of large-$N$ equivalences, which is known to hold in the ’t Hooft limit, can be extended to this very strongly coupled limit. Hence this limit may lead to a new way of studying corrections to the ’t Hooft limit, while keeping nice properties of the latter. As a concrete example, we describe large-$N$ equivalences between the Aharony, Bergman, Jafferis and Maldacena theory and its orientifold projection. The equivalence implies that operators neutral under the projection symmetry have the same correlation functions in two theories at large $N$. Usual field theory arguments are valid when ’t Hooft coupling $\lambda \sim N/k$ is fixed and observables can be computed by using a planar diagrammatic expansion. With the help of the AdS/CFT correspondence, we argue that the equivalence extends to stronger coupling regions, $N\gg k$, including the M-theory region $N\gg k^5$. We further argue that the orbifold/orientifold equivalences between certain Yang-Mills theories can also be generalized. Such equivalences can be tested both analytically and numerically. Based on calculations of the free energy, we conjecture that the equivalences hold because planar dominance persists beyond the ’t Hooft limit.

We consider rotating superfluid pionic liquid, with superfluidity being induced by isospin chemical potential. The rotation is known to result in a chiral current flowing along the axis of the rotation. We argue that in the case of superfluidity the chiral current is realized on fermionic zero modes propagating along vortices. The current evaluated in this way differs by a factor of 2 from the standard one. The reason is that the chiral charge is carried by zero modes which propagate with speed of light, and thus the liquid cannot be described by a single (local) velocity, like it is assumed in standard derivations.

We reconsider, in five-dimensional space-time, the issue of thick brane localized in the extra dimension by a kink formed by a scalar field. The localization is achieved by a sine-Gordon potential. Apart from a fundamental brane (where the scalar field is a monotonic function of the extra dimension [R. Koley and S. Kar, Classical Quantum Gravity 22, 753 (2005)]), we show that a series of new solutions exist as well, labeled by the number of zeros of the scalar field. These solutions are regular, localized on the brane, and mirror-symmetric with respect to the extra dimension. They form a tower of “excited branes”. The study of some perturbations of the solutions reveals that the new solutions are not stable. Finally, fermions are coupled to the scalar field by means of a Yukawa potential and their localization in the background of the new solutions is examined. It turns out that the excited branes can localize left and right chiral fermions either on the brane and/or in the bulk but close to the brane.

We study inflation and preheating in $F(\mathcal{R})$ supergravity characterized by two mass scales of a scalar degree of freedom (scalaron): $M$ (associated with the inflationary era) and $m$ (associated with the preheating era). The allowed values of the masses $M$ and $m$ are derived from the amplitude of the cosmic microwave background temperature anisotropies. We show that our model is consistent with the joint observational constraints of WMAP and other measurements in the regime where a sufficient amount of inflation (with the number of $e$-foldings larger than 50) is realized. In the low-energy regime relevant to preheating, we derive the effective scalar potential in the presence of a pseudoscalar field $\chi$ coupled to the inflaton (scalaron) field $\varphi$. If $m$ is much larger than $M$, we find that there exists a preheating stage in which the field perturbations $\delta \chi$ and $\delta \varphi$ rapidly grow by a broad parametric resonance.

Dwarf spheroidal galaxies compose one of the most dark matter dominated classes of objects, making them a set of targets to search for signals of dark matter annihilation. Recent developments in $\gamma$-ray astronomy, most importantly the launch of the Fermi-LAT instrument, have brought those targets into attention. Yet, no clear excess of $\gamma$-rays has been confirmed from these targets, resulting in some of the tightest limits on dark matter annihilation from indirect searches. In extracting limits from dwarf spheroidal galaxies, it is of great importance to properly take into account all relevant uncertainties. Those include the dark matter distribution properties of the dwarf spheroidals and the uncertainties on the underlying background. We revisit the limits on dark matter annihilation, from $\gamma$-rays studying a set of close-by dwarf spheroidal galaxies for which we have good understanding of the uncertainties in the dark matter distribution. For those targets, we perform and compare results for alternative methods in extracting the background $\gamma$-ray flux. This provides a method to discriminate among the dark matter annihilation targets, those that can give robust constraints. We finally present our tightest limits on dark matter annihilation that come only from the targets that ensure accurate understanding of both the $\gamma$-ray background and the dark matter distribution uncertainties.

We generalize the Lellouch-Lüscher formula, relating weak matrix elements in finite and infinite volumes, to the case of multiple strongly coupled decay channels into two scalar particles. This is a necessary first step on the way to a lattice quantum chromodynamics calculation of weak decay rates for processes such as $D\to \pi \pi$ and $D\to K\overline{K}$. We also present a field theoretic derivation of the generalization of Lüscher’s finite-volume quantization condition to multiple two-particle channels. We give fully explicit results for the case of two channels, including a form of the generalized Lellouch-Lüscher formula expressed in terms of derivatives of the energies of finite-volume states with respect to the box size. Our results hold for arbitrary total momentum and for degenerate or nondegenerate particles.

A comprehensive analysis on the light Higgs scenario (LHS) of the minimal supersymmetric standard model is performed in the framework of the nonuniversal Higgs mass model (NUHM). In the LHS, the lightest Higgs boson mass is lighter than 114.4 GeV, and the LEP bound is avoided because the coupling of the lightest Higgs boson with the $Z$ boson can be suppressed if other MSSM Higgs boson masses are also around 100–200 GeV. The NUHM is known to be the simplest framework realizing the LHS with consistent unifications of gaugino and sfermion masses at the grand unified theory scale. All important constraints from collider experiments, flavor-changing processes, and cosmological observations are considered in order to clarify the allowed region of the model parameter space, where the Markov chain Monte Carlo method is used to obtain the region. We show that the region is excluded by current LHC results for the SUSY particle searches. We discuss possible extensions to save the LHS. Even with such extensions, the measurement of $B_s\to {\mu }^{+}{\mu }^{-}$ would enable us to test the LHS in the near future.

I describe a procedure by which one can transform scattering amplitudes computed in the four-dimensional helicity scheme into properly renormalized amplitudes in the ’t Hooft-Veltman scheme. I describe a new renormalization program, based upon that of the dimensional reduction scheme and explain how to remove both finite and infrared-singular contributions of the evanescent degrees of freedom to the scattering amplitude.