Heavy colored scalar particles appear in a variety of new physics (NP) models and could be produced at the Large Hadron Collider. Knowing the total production cross section is important for searching for these states and establishing bounds on their masses and couplings. Using soft-collinear effective theory, we derive a factorization theorem for the process $pp\to SX$, where $S$ is a color-octet scalar, that is applicable to any NP model provided the dominant production mechanism is gluon-gluon fusion. The factorized result for the inclusive cross section is similar to that for the standard model Higgs production; however, differences arise due to color exchange between initial and final states. We provide formulas for the total cross section with large (partonic) threshold logarithms resummed to next-to-leading logarithm accuracy. The resulting $K$ factors are similar to those found in Higgs production. We apply our formalism to the Manohar-Wise model and find that the next-to-leading logarithm cross section is roughly 2 times (3 times) as large as the leading order cross section for a color-octet scalar of mass of 500 GeV (3 TeV). A similar enhancement should appear in any NP model with color-octet scalars.

Partial decay widths and branching fractions are calculated for the exclusive decays of the standard model Higgs boson into a pair of vector quarkonium states, $H\to J/\psi J/\psi$, $H\to {\rm Y}{\rm Y}$, $H\to J/\psi \varphi$, $H\to J/\psi {\rm Y}$, with relativistic corrections due to quark motion in mesons taken into account.

We compute the next-to-leading order (NLO) QCD corrections to the spin-independent and spin-dependent cross sections for the production of a single-hadron accompanied by an opposite jet in hadronic collisions. This process is being studied experimentally at RHIC, providing a new tool to unveil the polarized gluon distribution $\Delta g$. We perform a detailed analysis of the phenomenological impact of the observable at NLO accuracy and show that the preliminary data by the STAR collaboration confirms the idea of a small gluon polarization in the $0.05\lesssim x\lesssim 0.3$ range.

We study the inclusive decays of $D_s^{+}$ mesons, using data collected near the $D_s^{*\pm }{D}_s^{\mp }$ peak production energy $E_{\mathrm{cm}}=4170\mathrm{MeV}$ by the CLEO-c detector. We report the inclusive yields of $D_s^{+}$ decays to $K^{+}X$, $K^{-}X$, $K_S^{0}X$, ${\pi }^{+}X$, ${\pi }^{-}X$, ${\pi }^{0}X$, $\eta X$, ${\eta }^{\prime }X$, $\varphi X$, $\omega X$, and $f_0(980)X$, and also decays into pairs of kaons, $D_s^{+}\to K\overline{K}X$. Using these measurements, we obtain an overview of $D_s^{+}$ decays.

The AdS/CFT correspondence may connect the landscape of string vacua and the “atomic landscape” of condensed matter physics. We study the stability of a landscape of IR fixed points of $\mathcal{N}=2$ large $N$ gauge theories in $2+1$ dimensions, dual to Sasaki-Einstein compactifications of M theory, toward a superconducting state. By exhibiting instabilities of charged black holes in these compactifications, we show that many of these theories have charged operators that condense when the theory is placed at a finite chemical potential. We compute a statistical distribution of critical superconducting temperatures for a subset of these theories. With a chemical potential of 1 mV, we find critical temperatures ranging between 0.24 and 165 K.

General relativistic quasiequilibrium states of black hole-neutron star binaries are computed in the moving-puncture framework. We propose three conditions for determining the quasiequilibrium states and compare the numerical results with those obtained in the excision framework. We find that the results obtained in the moving-puncture framework agree with those in the excision framework and with those in the third post-Newtonian approximation for the cases that (i) the mass ratio of the binary is close to unity irrespective of the orbital separation, and (ii) the orbital separation is large enough ($m_0\Omega \lesssim 0.02$, where $m_0$ and $\Omega$ are the total mass and the orbital angular velocity, respectively) irrespective of the mass ratio. For $m_0\Omega \gtrsim 0.03$, both of the results in the moving-puncture and excision frameworks deviate, more or less, from those in the third post-Newtonian approximation. Thus the numerical results do not provide a quasicircular state, rather they seem to have a non-negligible eccentricity of order 0.01–0.1. We show by numerical simulation that a method in the moving-puncture framework can provide approximately quasicircular states in which the eccentricity is by a factor of $\sim 2$ smaller than those in quasiequilibrium given by other approaches.

Warp drives are very interesting configurations in general relativity: At least theoretically, they provide a way to travel at superluminal speeds, albeit at the cost of requiring exotic matter to exist as solutions of Einstein’s equations. However, even if one succeeded in providing the necessary exotic matter to build them, it would still be necessary to check whether they would survive to the switching on of quantum effects. Semiclassical corrections to warp-drive geometries have been analyzed only for eternal warp-drive bubbles traveling at fixed superluminal speeds. Here, we investigate the more realistic case in which a superluminal warp drive is created out of an initially flat spacetime. First of all we analyze the causal structure of eternal and dynamical warp-drive spacetimes. Then we pass to the analysis of the renormalized stress-energy tensor (RSET) of a quantum field in these geometries. While the behavior of the RSET in these geometries has close similarities to that in the geometries associated with gravitational collapse, it shows dramatic differences too. On one side, an observer located at the center of a superluminal warp-drive bubble would generically experience a thermal flux of Hawking particles. On the other side, such Hawking flux will be generically extremely high if the exotic matter supporting the warp drive has its origin in a quantum field satisfying some form of quantum inequalities. Most of all, we find that the RSET will exponentially grow in time close to, and on, the front wall of the superluminal bubble. Consequently, one is led to conclude that the warp-drive geometries are unstable against semiclassical backreaction.

We consider the signals of positrons and electrons from “exciting” dark matter annihilation. Because of the light ($m_{\varphi }\lesssim 1\mathrm{GeV}$) force carrier $\varphi$ into which the dark matter states can annihilate, the electrons and positrons are generally very boosted, yielding a hard spectrum, in addition to the low energy positrons needed for INTEGRAL observations of the Galactic center. We consider the relevance of this scenario for HEAT, PAMELA, and the WMAP “haze,” focusing on light ($m_{\varphi }\lesssim 2m_{\pi }$) $\varphi$ bosons, and find that significant signals can be found for all three, although significant signals generally require high dark matter densities. We find that measurements of the positron fraction are generally insensitive to the halo model, but do suffer significant astrophysical uncertainties. We discuss the implications for upcoming PAMELA results.

Classical lattice simulations of the Abelian Higgs model are used to investigate small-scale structure and loop distributions in cosmic string networks. Use of the field theory ensures that the small-scale physics is captured correctly. The results confirm analytic predictions of Polchinski and Rocha [29] for the two-point correlation function of the string tangent vector, with a power law from length scales of order the string core width up to horizon scale. An analysis of the size distribution of string loops gives a very low number density, of order 1 per horizon volume, in contrast with Nambu-Goto simulations. Further, our loop distribution function does not support the detailed analytic predictions for loop production derived by Dubath et al. [30]. Better agreement to our data is found with a model based on loop fragmentation [32], coupled with a constant rate of energy loss into massive radiation. Our results show a strong energy-loss mechanism, which allows the string network to scale without gravitational radiation, but which is not due to the production of string width loops. From evidence of small-scale structure we argue a partial explanation for the scale separation problem of how energy in the very low frequency modes of the string network is transformed into the very high frequency modes of gauge and Higgs radiation. We propose a picture of string network evolution, which reconciles the apparent differences between Nambu-Goto and field theory simulations.

We show a primordial nonlinear (“$f_{\mathrm{NL}}$”) term may produce unphysically large CMB anisotropy for a red-tilted primordial power spectrum ($n<1$) because of coupling to primordial fluctuation on the largest scale. We consider a primordial power spectrum models of a running spectral index, and a transition at very low wave numbers. We find that only negative running spectral index models are allowed, provided that there is no transition at a low wave numbers (i.e. $k\ll 1$). For models of a constant spectral index, we find $\log (k_c/k_0)\gtrsim -184$, at $1\sigma$ level, on the transition scale of sharp cutoff models, using recent CMB and SDSS data.

The modification of mesonic observables in a hot medium is analyzed as a tool to investigate the restoration of chiral and axial symmetries in the context of the Polyakov-loop extended Nambu–Jona-Lasinio model. The results of the extended model lead to the conclusion that the effects of the Polyakov loop are fundamental for reproducing lattice findings. In particular, the partial restoration of the chiral symmetry is faster in the Polyakov–Nambu–Jona-Lasinio model than in the Nambu–Jona-Lasinio one, and it is responsible for several effects: the meson-quark coupling constants show a remarkable difference in both models, there is a faster tendency to recover the Okubo-Zweig-Iizuka rule, and finally the topological susceptibility nicely reproduces the lattice results around $T/T_c\approx 1.0$.

The Ginsparg-Wilson relation is extended to interacting field theories with general linear symmetries. Our relation encodes the remnant of the original symmetry in terms of the blocked fields and guides the construction of invariant lattice actions. We apply this approach in the case of lattice supersymmetry. An additional constraint has to be satisfied because of the appearance of a derivative operator in the symmetry transformations. The solution of this constraint leads to nonlocal SLAC-type derivatives. We investigate the corresponding kinetic operators on the lattice within an exact solution of supersymmetric quantum mechanics. These solutions—analogs of the overlap operator for supersymmetry—can be made local through a specific choice of the blocking kernel. We show that the symmetry relation allows for local lattice symmetry operators as well as local lattice actions. We argue that for interacting theories the lattice action is polynomial in the fields only under special circumstances, which is exemplified within an exact solution.

Motivated by the gluon-chain model of flux tube formation, we compute and diagonalize the transfer matrix in lattice SU(2) gauge theory for states containing heavy static quark-antiquark sources, with separations up to one Fermi. The elements of the transfer matrix are calculated by variational Monte Carlo methods, in a basis of states obtained by acting on the vacuum state with zero-, one-, and two-gluon operators in Coulomb gauge. The color Coulomb potential is obtained from the zero-gluon to zero-gluon element of the transfer matrix, and it is well known that while this potential is asymptotically linear, it has a slope which is 2 to 3 times larger than the standard asymptotic string tension. We show that the addition of one- and two-gluon states results in a potential which is still linear, but the disagreement with the standard asymptotic string tension is reduced to 38% for the variational states used in this study, at the largest value of $\beta =4/g^2=2.4$ considered.

Factorization is the central ingredient in any theoretical prediction for collider experiments. We introduce a factorization formalism that can be applied to any desired observable, like event shapes or jet observables, for any number of jets and a wide range of jet algorithms in leptonic or hadronic collisions. This is achieved by using soft-collinear effective theory to prove the formal factorization of a generic fully differential cross section in terms of a hard coefficient, and generic jet and soft functions. In this formalism, whether a given observable factorizes in the usual sense, depends on whether it is inclusive enough, so the jet functions can be calculated perturbatively. The factorization formula for any such observable immediately follows from our general result, including the precise definition of the jet and soft functions appropriate for the observable in question. As examples of our formalism, we work out several results in two-jet production for both $e^{+}{e}^{-}$ and $pp$ collisions. For the latter, we also comment on how our formalism allows one to treat underlying events and beam remnants.

We study the hadronic production of $B_s$ and $B_s^{*}$ mesons within the fixed-flavor-number scheme, in which the dominant gluon-gluon fusion mechanism is dealt with by using the complete ${\alpha }_s^4$ approach. Main theoretical uncertainties for $B_s$ and $B_s^{*}$ production at the Tevatron and LHC are presented. It is found that when $m_s$ increases by steps of 0.1 GeV, the integrated cross section of $B_s^{(*)}$ decreases by 80%–100%. When $m_b$ increases by steps of 0.1 GeV, it changes by $\sim 10\%$, while the uncertainties caused by the parton distribution function and the factorization scale vary within the region of $\frac{1}{5}$ to $\frac{1}{3}$. Considering a possible kinematic cut on the transverse momentum and the rapidity cut for the detectors at the Tevatron and LHC, we also make estimations on the $B_s$ and $B_s^{*}$ production with various kinematic cuts.

The QCD sum rule method is formulated for the strangeness $+1$ pentaquark baryon with isospin $I=0$ and spin-parity $J^{\pi }={\frac{3}{2}}^{\pm }$. The spin-$\frac{3}{2}$ states are considered to be narrower than the spin-$\frac{1}{2}$ ones, and thus may provide a natural explanation for the experimentally observed narrow width of ${\Theta }^{+}$. In order to obtain reliable results in QCD sum rule calculations, we stress the importance of establishing a wide Borel window, where convergence of the operator product expansion and sufficient low-mass strength of the spectral function are guaranteed. To this end, we employ the difference of two independent correlators so that the high-energy continuum contribution is suppressed. The stability of the physical quantities against the Borel mass is confirmed within the Borel window. It is found that the sum rule gives positive evidence for the $(I,J^{\pi })=(0,{\frac{3}{2}}^{+})$ state with a mass of about $1.4\pm 0.2\mathrm{GeV}$, while we cannot extract any evidence for the $(0,{\frac{3}{2}}^{-})$ state.

We analyze the newest diffractive deep inelastic scattering data from the DESY collider HERA with the help of dipole models. We find good agreement with the data on the diffractive structure functions provided the diffractive open charm contribution is taken into account. However, the region of large diffractive mass (small values of a parameter $\beta$) needs some refinement with the help of an additional gluon radiation.

This paper reports a measurement of the cross section for the pair production of top quarks in $p\overline{p}$ collisions at $\sqrt{s}=1.96\mathrm{TeV}$ at the Fermilab Tevatron. The data were collected from the CDF run II detector in a set of runs with a total integrated luminosity of $1.1{\mathrm{fb}}^{-1}$. The cross section is measured in the dilepton channel, the subset of $t\overline{t}$ events in which both top quarks decay through $t\to Wb\to \ell \nu b$, where $\ell =e$, $\mu$, or $\tau$. The lepton pair is reconstructed as one identified electron or muon and one isolated track. The use of an isolated track to identify the second lepton increases the $t\overline{t}$ acceptance, particularly for the case in which one $W$ decays as $W\to \tau \nu$. The purity of the sample may be further improved at the cost of a reduction in the number of signal events, by requiring an identified $b$ jet. We present the results of measurements performed with and without the request of an identified $b$ jet. The former is the first published CDF result for which a $b$-jet requirement is added to the dilepton selection. In the CDF data there are 129 pretag $\mathrm{\text{lepton}}+\mathrm{\text{track}}$ candidate events, of which 69 are tagged. With the tagging information, the sample is divided into tagged and untagged subsamples, and a combined cross section is calculated by maximizing a likelihood. The result is ${\sigma }_{t\overline{t}}=9.6\pm 1.2(\mathrm{stat}{)}_{-0.5}^{+0.6}(\mathrm{sys})\pm 0.6(\mathrm{lum})\mathrm{pb}$, assuming a branching ratio of $\mathrm{BR}(W\to \ell \nu )=10.8\%$ and a top mass of $m_t=175\mathrm{GeV}/c^2$.

We report the measurement of charged $D^{*}$ mesons in inclusive jets produced in proton-proton collisions at a center-of-mass energy $\sqrt{s}=200\mathrm{GeV}$ with the STAR experiment at the Relativistic Heavy Ion Collider. For $D^{*}$ mesons with fractional momenta $0.2<z<0.5$ in inclusive jets with 11.5 GeV mean transverse energy, the production rate is found to be $N(D^{*+}+D^{*-})/N(\mathrm{jet})=0.015\pm 0.008(\mathrm{stat})\pm 0.007(\mathrm{sys})$. This rate is consistent with perturbative QCD evaluation of gluon splitting into a pair of charm quarks and subsequent hadronization.

We report a set of measurements of particle production in inelastic $p\overline{p}$ collisions collected with a minimum-bias trigger at the Tevatron Collider with the CDF II experiment. The inclusive charged particle transverse momentum differential cross section is measured, with improved precision, over a range about ten times wider than in previous measurements. The former modeling of the spectrum appears to be incompatible with the high particle momenta observed. The dependence of the charged particle transverse momentum on the event particle multiplicity is analyzed to study the various components of hadron interactions. This is one of the observable variables most poorly reproduced by the available Monte Carlo generators. A first measurement of the event transverse energy sum differential cross section is also reported. A comparison with a pythia prediction at the hadron level is performed. The inclusive charged-particle differential production cross section is fairly well reproduced only in the transverse momentum range available from previous measurements. At higher momentum the agreement is poor. The transverse energy sum is poorly reproduced over the whole spectrum. The dependence of the charged particle transverse momentum on the particle multiplicity needs the introduction of more sophisticated particle production mechanisms, such as multiple parton interactions, in order to be better explained.