We discuss the prospects for production and detection of fermiophobic bosons (exotic bosons decaying only to standard model gauge bosons) at the LHC, and describe simple methods for determining spin. We consider two complementary approaches to spin determination: the search for decays in the diphoton channel, and the comparison of events with no extra spectator jets to those with one extra jet. We show that these approaches can together allow the fermiophobic boson’s spin to be determined over a wide range of parameter space. We study both even and odd parity states.

I adapt a numerical method, previously applied to investigate the Yang-Mills vacuum wave functional, to the problem of extracting the effective Polyakov line action from $\mathrm{SU}(N)$ lattice gauge theories, with or without matter fields. The method can be used to find the variation of the effective Polyakov line action along any trajectory in field configuration space; this information is sufficient to determine the potential term in the action and strongly constrains the possible form of the kinetic term. The technique is illustrated for both pure and gauge Higgs SU(2) lattice gauge theory at finite temperature. A surprise, in the pure gauge theory, is that the potential of the corresponding Polyakov line action contains a nonanalytic (yet center-symmetric) term proportional to $|P{|}^3$, where $P$ is the trace of the Polyakov line at a given point, in addition to the expected analytic terms proportional to even powers of $P$.

We formulate an extended linear $\sigma$ model of a quarkonia nonet and a tetraquark nonet as well as a complex isosinglet (glueball) by virtue of chiral symmetry $S{U}_L(3)\times S{U}_R(3)$ and $U_A(1)$ symmetry. In the linear realization formalism, we study the mass spectra and components of the low-lying scalars and pseudoscalars in this model. The mass matrices for physical states are obtained and the glueball candidates are examined. We find that the model can accommodate the mass spectra of low-lying states quite well. Our fits indicate that the most glueball-like scalar should be 2 GeV or higher while the glueball pseudoscalar is $\eta (1756)$. We also examine the parameter region where the lightest isoscalar $f_0(600)$ can be the glueball and quarkonia dominant but find such a parameter region may be confronted with the problem of the unbounded vacuum from below.

In the present paper we describe the set of form factors for hadronic $\tau$ decays based on Resonance Chiral Theory. The technical implementation of the form factors in fortran code is also explained. It is shown how it can be installed into the TAUOLA Monte Carlo program. Then it is rather easy to implement into software environments of not only Belle and BABAR collaborations but also for fortran and $\mathrm{C}++$ applications of LHC. The description of the current for each $\tau$ decay mode is complemented with technical numerical tests. The set is ready for fits, paramxers to be used in fits are explained. Arrangements to work with the experimental data not requiring unfolding are prepared. Hadronic currents, ready for confrontation with the $\tau$ decay data, but not yet ready for the general use, cover more than 88% of hadronic $\tau$ decay width.

From a picture of the $X(3872)$ where the resonance is a bound state of $\overline{D}{D}^{*}-\mathrm{c}.\mathrm{c}.$, we evaluate the decay width into the $J/\psi \gamma$ channel, which is sensitive to the internal structure of this state. For this purpose we evaluate the loops through which the $X(3872)$ decays into its components, and the $J/\psi$ and the photon are radiated from these components. We use the local hidden gauge approach extrapolated to $SU(4)$ with a particular $SU(4)$ breaking. The radiative decay involves anomalous couplings, and we obtain acceptable values which are compared to experiments and results of other calculations. Simultaneously, we evaluate the decay rate for the $X(3872)$ into $J/\psi \omega$ and $J/\psi \rho$, and the results obtained for the ratio of these decay widths are compatible with the experiment. We also show that considering only the ${\overline{D}}^0{D}^{*0}-\mathrm{c}.\mathrm{c}.$ component in the radiative decay reduces the partial decay width in more than three orders of magnitude, in large discrepancy with experiment.

We study a twist decomposition of diffractive structure functions in the diffractive deep inelastic scattering at HERA. At low $Q^2$ and at large energy, the data exhibit a strong excess, up to about 100%, above the twist-2 next-to-leading order Dokshitzer-Gribov-Lipatov-Altarelli-Parisi description. The excess is consistent with higher twist effects. It is found that complementing the Dokshitzer-Gribov-Lipatov-Altarelli-Parisi fit by twist-4 and -6 components of the Golec-Biernat-Wüsthoff saturation model leads to a good description of data at low $Q^2$. We conclude that the diffractive deep inelastic scattering at HERA provides the first strong evidence of higher twist effects in deep inelastic scattering.

We use cosmography to present constraints on the kinematics of the Universe, without postulating any underlying theoretical model. To this end, we use a Monte Carlo Markov chain analysis to perform comparisons to the supernova Ia Union 2 compilation, combined with the Hubble Space Telescope measurements of the Hubble constant, and the Hubble parameter data sets. We introduce a sixth order cosmographic parameter and show that it does not enlarge considerably the posterior distribution when comparing to the fifth order results. We also propose a way to construct viable parameter variables to be used as alternatives of the redshift $z$. These can overcome both the problems of divergence and lack of accuracy associated with the use of $z$. Moreover, we show that it is possible to improve the numerical fits by reparametrizing the cosmological distances. In addition, we constrain the equation of state of the Universe as a whole by the use of cosmography. Thus, we derive expressions which can be directly used to fit the equation of state and the pressure derivatives up to fourth order. To this end, it is necessary to depart from a pure cosmographic analysis and to assume the Friedmann equations as valid. All our results are consistent with the $\Lambda \mathrm{CDM}$ model, although alternative fluid models, with nearly constant pressure and no cosmological constant, match the results accurately as well.

Pulsar timing arrays (PTAs) will be sensitive to a finite number of gravitational wave (GW) “point” sources (e.g. supermassive black hole binaries). $N$ quiet pulsars with accurately known distances $d_{\mathrm{pulsar}}$ can characterize up to $2N/7$ distant chirping sources per frequency bin $\Delta f_{\mathrm{gw}}=1/T$ and localize them with “diffraction-limited” precision $\delta \theta \gtrsim (1/\mathrm{SNR})({\lambda }_{\mathrm{gw}}/d_{\mathrm{pulsar}})$. Even if the pulsar distances are poorly known, a PTA with $F$ GW frequency bins can still characterize up to $(2N/7)(1-\frac{1}{2F})$ sources per bin, and the quasisingular pattern of timing residuals in the vicinity of a GW source still allows the source to be localized quasitopologically within roughly the smallest quadrilateral of quiet pulsars that encircles it on the sky, down to a limiting resolution $\delta \theta \gtrsim (1/\mathrm{SNR})\sqrt{{\lambda }_{\mathrm{gw}}/d_{\mathrm{pulsar}}}$. PTAs may be unconfused, even at the lowest GW frequencies: in that case, standard analysis techniques designed to detect a stochastic GW background would be incomplete and suboptimal, whereas matched filtering could provide more information and sensitivity.

Inhomogeneous quantum cosmology is modeled as a dynamical system of discrete patches, whose interacting many-body equations can be mapped to a nonlinear minisuperspace equation by methods analogous to Bose—Einstein condensation. Complicated gravitational dynamics can therefore be described by more-manageable equations for finitely many degrees of freedom, for which powerful solution procedures are available, including effective equations. The specific form of nonlinear and nonlocal equations suggests new questions for mathematical and computational investigations, and general properties of nonlinear wave equations lead to several new options for physical effects and tests of the consistency of loop quantum gravity. In particular, our quantum cosmological methods show how sizeable quantum corrections in a low-curvature Universe can arise from tiny local contributions adding up coherently in large regions.

We extend our investigation of resonance production in the Sakai-Sugimoto model to the case of negative parity baryon resonances. Using holographic techniques we extract the generalized Dirac and Pauli baryon form factors as well as the helicity amplitudes for these baryonic states. Identifying the first negative parity resonance with the experimentally observed $S_{11}(1535)$, we find reasonable agreement with experimental data from the JLab-CLAS collaboration. We also estimate the contribution of negative parity baryons to the proton structure functions.

In this work we present the study of the renormalizability of the Generalized Quantum Electrodynamics (${\mathrm{GQED}}_4$). We begin the article by reviewing the on-shell renormalization scheme applied to ${\mathrm{GQED}}_4$. Thereafter, we calculate the explicit expressions for all the counter-terms at one-loop approximation and discuss the infrared behavior of the theory as well. Next, we explore some properties of the effective coupling of the theory which would give an indictment of the validity regime of theory: $m^2\le k^2<m_P^2$. Afterwards, we make use of experimental data from the electron anomalous magnetic moment to set possible values for the theory free parameter through the one-loop contribution of Podolsky mass-dependent term to Pauli’s form factor $F_2(q^2)$.

We present a model for cosmological inflation which has a natural “turn on” and a natural “turn off” mechanism. In our model inflation is driven by the Hawking-like radiation that occurs in Friedmann-Robertson-Walker (FRW) space-time. This Hawking-like radiation results in an effective negative pressure “fluid” which leads to a rapid period of expansion in the very early Universe. As the Universe expands the FRW Hawking temperature decreases and the inflationary expansion turns off and makes a natural transition to the power-law expansion of a radiation dominated universe. The turn on mechanism is more speculative, but is based on the common hypothesis that in a quantum theory of gravity at very high temperatures/high densities Hawking radiation will stop. Applying this speculation to the very early Universe implies that the Hawking-like radiation of the FRW space-time will be turned off and therefore the inflation driven by this radiation will turn off.

Primordial magnetic fields (PMF) can create polarization $B$-modes in the cosmic microwave background (CMB) through Faraday rotation (FR), leading to nontrivial two-point and four-point correlators of the CMB temperature and polarization. We discuss the detectability of primordial magnetic fields using different correlators and evaluate their relative merits. We have fully accounted for the contamination by weak lensing, which contributes to the variance, but whose contribution to the four-point correlations is orthogonal to that of FR. We show that a Planck-like experiment can detect scale-invariant PMF of nG strength using the FR diagnostic at 90 GHz, while realistic future experiments at the same frequency can detect ${10}^{-10}\mathrm{G}$. Utilizing multiple frequencies will improve on these prospects, making FR of CMB a powerful probe of scale-invariant PMF.

The LHC collaborations have recently announced evidence for the production of a “Higgs-like” boson with mass near 125 GeV. The properties of the new particle are consistent (within still quite large uncertainties) with those of the Higgs boson predicted in the Standard Model. This discovery comes nearly ten years after a combined analysis of the four LEP experiments showed a mild excess of Higgs-like events with a mass near 98 GeV. I show that both groups of events can be explained simultaneously in the minimal supersymmetric extension of the Standard Model, in terms of the production and decay of the two neutral $CP$-even Higgs bosons predicted by this model, and explore the phenomenological consequences of this explanation.

A calculation of the interaction potential of two heavy-light mesons in lattice QCD is used to study the existence of tetraquark bound states. The interaction potential of the tetraquark system is calculated on the lattice with $2+1$ flavors of dynamical fermions with lattice interpolating fields constructed using color wave propagators. These propagators provide a method for constructing all-to-all spatially smeared interpolating fields, a technique which allows for a better overlap with the ground state wave function as well as reduced statistical noise. Potentials are extracted for 24 distinct channels, and are fit with a phenomenological nonrelativistic quark model potential, from which a determination of the existence of bound states is made via numerical solution of the two body radial Schrödinger equation.

We consider the ($2+1$) flavor Polyakov quark meson model and study the fluctuations (correlations) of conserved charges up to sixth (fourth) order. A comparison is made with lattice data wherever available and overall good qualitative agreement is found, more so for the case of the normalized susceptibilities. The model predictions for the ratio of susceptibilities go to that of an ideal gas of hadrons as in hadron resonance gas model at low temperatures while at high temperature the values are close to that of an ideal gas of massless quarks. Our study provides a strong basis for the use of the Polyakov quark meson model as an effective model to understand the topology of the QCD phase diagram.

Within the collinear twist-3 framework, we analyze the double-spin asymmetry in collisions between longitudinally polarized nucleons and transversely polarized nucleons with focus on hadron and jet production. As was the case in direct photon production, the double-spin dependent cross section for hadron and jet production has the advantage of involving a complete set of collinear twist-3 functions for a transversely polarized nucleon. In addition, we outline further benefits of this observable for a potential future measurement at the Relativistic Heavy Ion Collider, which includes insight on the gluon helicity distribution as well as information on the Efremov-Teryaev-Qiu-Sterman function $T_F(x,x)$ that plays a crucial role in single-spin asymmetries.

A generalized top-spin analysis proposed some time ago in the context of the standard model and subsequently studied in varying contexts is now applied primarily to the case of $e^{+}{e}^{-}\to t\overline{t}$ with transversely polarized beams. This extends our recent work with new physics couplings of scalar ($S$) and tensor ($T$) types. We carry out a comprehensive analysis assuming only the electron beam to be transversely polarized, which is sufficient to probe these interactions, and also eliminates any azimuthal angular dependence due to the standard model or new physics of the vector ($V$) and axial-vector ($A$) type interactions. We then consider new physics of the general four-Fermi type of $V$ and $A$ type with both beams transversely polarized and discuss implications with longitudinal polarization as well. The generalized spin bases are all investigated in the presence of either longitudinal or transverse beam polarization to look for appreciable deviation from the SM prediction in case of the new physics. 90% confidence level limits are obtained on the interactions for the generalized spin bases with realistic integrated luminosity. In order to achieve this we present a general discussion based on helicity amplitudes and derive a general transformation matrix that enables us to treat the spin basis. We find that beamline basis combined with transverse polarization provides an excellent window of opportunity both for $S$, $T$ and $V$, $A$ new physics, followed by the off-diagonal basis. The helicity basis is shown to be the best in case of longitudinal polarization to look for new physics effects due to $V$ and $A$.

We present results for dihadron fragmentation functions from the Nambu–Jona-Lasinio-jet model evolved from the model scale to a typical experimental scale of $4{\mathrm{GeV}}^2$. The numerical method used in this evolution is discussed in detail. The effect of evolution on the shapes of the dihadron fragmentation functions is discussed for a doubly favored process ($u\to {\pi }^{+}{\pi }^{-}$), as well as a singly favored ($u\to {\pi }^{+}{K}^{-}$) process involving light quarks. Finally, we explore the production of $K^{+}{K}^{-}$ pairs from an initial $u$, $d$ or $s$ quark.