We consider some specific inverse problem or “bottom-up” reconstruction strategies at the CERN LHC for both general and constrained minimal supersymmetric standard model (MSSM) parameters, starting from a plausibly limited set of sparticle identification and mass measurements, using mainly gluino/squark cascade decays, plus eventually the lightest Higgs boson mass. For the three naturally separated sectors of gaugino/Higgsino, squark/slepton, and Higgs parameters, we examine different step-by-step algorithms based on rather simple, entirely analytical, inverted relations between masses and basic MSSM parameters. This includes also reasonably good approximations of some of the relevant radiative correction calculations. We distinguish the constraints obtained for a general MSSM from those obtained with universality assumptions in the three different sectors. Our results are compared at different stages with the determination from more standard “top-down” fit of models to data, and finally combined into a global determination of all the relevant parameters. Our approach gives complementary information to more conventional analysis, and is not restricted to the specific LHC measurement specificities. In addition, the bottom-up renormalization group evolution of general MSSM parameters, being an important ingredient in this framework, is illustrated as a new publicly available option of the MSSM spectrum calculation code SuSpect.

We discuss the isentropic trajectories on the QCD phase diagram in the temperature and the quark chemical potential plane using the Nambu–Jona-Lasinio model with the Polyakov loop coupling. We impose a constraint on the strange quark chemical potential so that the strange quark density is zero, which is the case in the ultra relativistic heavy-ion collisions. We compare our numerical results with the truncated estimates by the Taylor expansion in terms of the chemical potential to quantify the reliability of the expansion used in the lattice QCD simulation. We finally discuss the strange quark chemical potential induced by the strangeness neutrality condition and relate it to the ratio of the Polyakov loop and the anti-Polyakov loop.

A generalized linear sigma model for low-energy QCD is employed to study the quark structure of eight low-lying scalar isomultiplets as well as eight low-lying pseudoscalar isomultiplets. The model, building on earlier work, assumes the possible mixing of quark antiquark states with others made of two quarks and two antiquarks. No a priori assumption is made about the quark contents of the states, which emerge as predictions. An amusing and contrasting pattern for the quark structure is found; the lighter conventional pseudoscalars are, as expected, primarily of two-quark type whereas the lighter scalars have very large four-quark admixtures. The new feature of the present paper compared to earlier ones in this series involves the somewhat subtle and complicated effects of SU(3) flavor breaking. They do not alter the general pattern of two-quark vs four-quark mixing obtained in the SU(3)symmetric case but, of course, give a more detailed picture.

In addition to the inclusive cross sections discussed within the QCD-parton model, in the regime of multiple parton interactions, different and more exclusive cross sections become experimentally viable and may be suitably measured. Indeed, in its study of double parton collisions, the quantity measured by the CDF was an “exclusive” rather than an inclusive cross section. The nonperturbative input to the “exclusive” cross sections is different with respect to the nonperturbative input of the inclusive cross sections and involves correlation terms of the hadron structure already at the level of single parton collisions. The matter is discussed in details keeping explicitly into account the effects of double and of triple parton collisions.

We investigate the reconstruction of high $p_T$ hadronically decaying top quarks at the Large Hadron Collider. One of the main challenges in identifying energetic top quarks is that the decay products become increasingly collimated. This reduces the efficacy of conventional reconstruction methods that exploit the topology of the top quark decay chain. We focus on the cases where the decay products of the top quark are reconstructed as a single jet, a “top jet.” The most basic “top-tagging” method based on jet mass measurement is considered in detail. To analyze the feasibility of the top-tagging method, both theoretical and experimental aspects of the large QCD jet background contribution are examined. Based on a factorization approach, we derive a simple analytic approximation for the shape of the QCD jet mass spectrum. We observe very good agreement with the Monte Carlo simulation. We consider high-$p_T$ $t\overline{t}$ production in the standard model as an example, and show that our theoretical QCD jet mass distributions can efficiently characterize the background via sideband analyses. We show that with $25{\mathrm{fb}}^{-1}$ of data, our approach allows us to resolve top jets with $p_T\ge 1\mathrm{TeV}$, from the QCD background, and about 1.5 TeV top jets with $100{\mathrm{fb}}^{-1}$, without relying on $b$-tagging. To further improve the significance we consider jet shapes (recently analyzed in [10]), which resolve the substructure of energy flow inside cone jets. A method of measuring the top quark polarization by using the transverse momentum of the bottom quark is also presented. The main advantages of our approach are (i) the mass distributions are driven by first principle calculations, instead of relying solely on Monte Carlo simulation; (ii) for high $p_T$ jets ($p_T\ge 1\mathrm{TeV}$), IR-safe jet shape variables are robust against detector resolution effects. Our analysis can be applied to other boosted massive particles such as the electroweak gauge bosons and the Higgs.

We generalize to three active flavors a previous two-flavor model for the resonant spin flavor conversion of solar neutrinos to sterile ones, a mechanism which is added to the well-known large mixing angle (LMA) one. The transition magnetic moments from the muon and tau neutrinos to the sterile play the dominant role in fixing the amount of active flavor suppression. We also show, through numerical integration of the evolution equations, that the data from all solar neutrino experiments except Borexino exhibit a clear preference for a sizable magnetic field either in the convection zone or in the core and radiation zone. This is possibly related to the fact that the data from the first set are average ones taken during a period of mostly intense solar activity, whereas in contrast Borexino data were taken during a period of quiet Sun. We argue that the solar neutrino experiments are capable of tracing the possible modulation of the solar magnetic field. Those monitoring the high-energy neutrinos, namely, the ${}^8\mathrm{B}$ flux, appear to be sensitive to a field modulation either in the convection zone or in the core and radiation zone. Those monitoring the low-energy fluxes will be sensitive to the second type of solar field profiles only. In this way Borexino alone may play an essential role, since it examines both energy sectors, although experimental redundancy from other experiments will be most important.

We analyze the structure of the nonunitary leptonic mixing matrix in the inverse seesaw model with heavy singlets accessible at the LHC. In this model, unlike in the usual TeV seesaw scenarios, the low-scale right-handed neutrinos do not suffer from naturalness issues. Underlying correlations among various parameters governing the nonunitarity effects are established, which leads to a considerable improvement of the generic nonunitarity bounds. In view of this, we study the discovery potential of the nonunitarity effects at future experiments, focusing on the sensitivity limits at a neutrino factory.

We present a measurement of the top quark mass with $t\overline{t}$ dilepton events produced in $p\overline{p}$ collisions at the Fermilab Tevatron ($\sqrt{s}=1.96\mathrm{TeV}$) and collected by the CDF II detector. A sample of 328 events with a charged electron or muon and an isolated track, corresponding to an integrated luminosity of $2.9{\mathrm{fb}}^{-1}$, are selected as $t\overline{t}$ candidates. To account for the unconstrained event kinematics, we scan over the phase space of the azimuthal angles $({\varphi }_{{\nu }_1},{\varphi }_{{\nu }_2})$ of neutrinos and reconstruct the top quark mass for each ${\varphi }_{{\nu }_1}$, ${\varphi }_{{\nu }_2}$ pair by minimizing a ${\chi }^2$ function in the $t\overline{t}$ dilepton hypothesis. We assign ${\chi }^2$-dependent weights to the solutions in order to build a preferred mass for each event. Preferred mass distributions (templates) are built from simulated $t\overline{t}$ and background events, and parametrized in order to provide continuous probability density functions. A likelihood fit to the mass distribution in data as a weighted sum of signal and background probability density functions gives a top quark mass of ${165.5}_{-3.3}^{+3.4}(\mathrm{stat})\pm 3.1(\mathrm{syst})\mathrm{GeV}/c^2$.

We present a time-dependent Dalitz plot measurement of $CP$ violation parameters in $B^0\to K_S^0{\pi }^{+}{\pi }^{-}$ decays. These results are obtained from a large data sample that contains $657\times {10}^6$ $B\overline{B}$ pairs collected at the ${\rm Y}(4S)$ resonance with the Belle detector at the KEKB asymmetric-energy $e^{+}{e}^{-}$ collider. For the $CP$ violation parameters, we obtain two consistent solutions that describe the data well. The first of these solutions may be preferred by external information from other measurements. There is no evidence for direct $CP$ violation in $B^0\to {\rho }^0(770)K_S^0$, $B^0\to f_0(980)K_S^0$ and $B^0\to K^{*+}(892){\pi }^{-}$, while measurements of mixing-induced $CP$ violation in $B^0\to {\rho }^0(770)K_S^0$ and $B^0\to f_0(980)K_S^0$ decays are consistent with that of $b\to c\overline{c}s$ decays. We also measured the phase difference between $B^0\to K^{*+}(892){\pi }^{-}$ and ${\overline{B}}^0\to K^{*-}(892){\pi }^{+}$, which may be used to extract ${\varphi }_3$.

We present a new measurement of the $e^{+}{e}^{-}\to J/\psi c\overline{c}$ cross section where the $c\overline{c}$ pair can fragment either into charmed hadrons or a charmonium state. In the former case the $J/\psi$ and a charmed hadron are reconstructed, while the latter process is measured using the recoil mass technique, which allows the identification of two-body final states without reconstruction of one of the charmonia. The measured $e^{+}{e}^{-}\to J/\psi c\overline{c}$ cross section is $(0.74\pm 0.08\genfrac{}{}{0ex}{}{+0.09}{-0.08})\mathrm{pb}$, and the $e^{+}{e}^{-}\to J/\psi X_{\mathrm{non}\mathrm{\text{−}}c\overline{c}}$ cross section is $(0.43\pm 0.09\pm 0.09)\mathrm{pb}$. We note that the measured cross sections are obtained from a data sample with the multiplicity of charged tracks in the event larger than 4; corrections for the effect of this requirement are not performed as this cannot be done in a model-independent way. The analysis is based on a data sample with an integrated luminosity of $673{\mathrm{fb}}^{-1}$ recorded near the ${\rm Y}(4S)$ resonance with the Belle detector at the KEKB $e^{+}{e}^{-}$ asymmetric-energy collider.

The high value of brane tension has a crucial role in recovering Einstein’s general relativity at low energies. In the framework of a recently developed formalism with variable brane tension, one can pose the question of whether it was always that high. In analogy with fluid membranes, in this paper we allow for temperature-dependent brane tension, according to the corresponding law established by Eötvös. For cosmological branes this assumption leads to several immediate consequences: (a) The brane universe was created at a finite temperature $T_c$ and scale factor $a_{\min }$. (b) Both the brane tension and the four-dimensional gravitational coupling “constant” increase with the scale factor from zero to asymptotic values. (c) The four-dimensional cosmological constant evolves with $a$, starting with a huge negative value, passing through zero, finally reaching a small positive value. Such a scale-factor–dependent cosmological constant is able to generate a surplus of attraction at small $a$ (as dark matter does) and a late-time repulsion at large $a$ (dark energy). In the particular toy model discussed here, the evolution of the brane tension is compensated by energy interchange between the brane and the fifth dimension, such that the continuity equation holds for the cosmological fluid. The resulting cosmology closely mimics the standard model at late times, a decelerated phase being followed by an accelerated expansion. The energy absorption of the brane drives the five-dimensional space-time towards maximal symmetry, becoming anti–de Sitter.

In alternative theories of gravity, designed to produce cosmic acceleration at the current epoch, the growth of large scale structure can be modified. We study the potential of upcoming and future tomographic surveys such as Dark Energy Survey (DES) and Large Synoptic Survey Telescope (LSST), with the aid of cosmic microwave background (CMB) and supernovae data, to detect departures from the growth of cosmic structure expected within general relativity. We employ parametric forms to quantify the potential time- and scale-dependent variation of the effective gravitational constant and the differences between the two Newtonian potentials. We then apply the Fisher matrix technique to forecast the errors on the modified growth parameters from galaxy clustering, weak lensing, CMB, and their cross correlations across multiple photometric redshift bins. We find that even with conservative assumptions about the data, DES will produce nontrivial constraints on modified growth and that LSST will do significantly better.

In this paper we fully calculate the non-Gaussianity of primordial curvature perturbation of the island universe by using the second order perturbation equation. We find that for the spectral index $n_s\simeq 0.96$, which is favored by current observations, the non-Gaussianity level $f_{\mathrm{NL}}$ seen in an island will generally lie between 30 and 60, which may be tested by the coming observations. In the landscape, the island universe is one of anthropically acceptable cosmological histories. Thus the results obtained in some sense mean the coming observations, especially the measurement of non-Gaussianity, will be significant to clarify how our position in the landscape is populated.

We introduce a new supercurrent in the electroweak sector of the standard model. Its interaction with the hypergauge field influences the mass of the $Z$ boson but has no effect on the $W^{\pm }$ boson masses. In the leptonic sector it affects the numerical value of the vector and axial coupling constants between neutral currents and the $Z$ boson, and a comparison with experimental values yields an upper bound to the strength of the coupling between the supercurrent and the hypergauge field. In the baryonic sector the supercurrent gives a new contribution to the anomaly equation for baryon number current. As a consequence it may have an effect on baryogenesis.

We investigate gauge coupling unification at 2-loops for theories with 5 extra vectorlike SU(5) fundamentals added to the minimal supersymmetric standard model (MSSM). This is a borderline case where unification is only predicted in certain regions of parameter space. We establish a lower bound on the scale for the masses of the extra flavors, as a function of the sparticle masses. Models far outside of the bound do not predict unification at all (but may be compatible with unification), and models outside but near the boundary cannot reliably claim to predict it with an accuracy comparable to the MSSM prediction. Models inside the boundary can work just as well as the MSSM.

Motivated by the galactic positron excess seen by PAMELA and ATIC/PPB-BETS, we propose that dark matter is a TeV-scale particle that annihilates into a pseudoscalar “axion.” The positron excess and the absence of an antiproton or gamma ray excess constrain the axion mass and branching ratios. In the simplest realization, the axion is associated with a Peccei-Quinn symmetry, in which case it has a mass around 360–800 MeV and decays into muons. We present a simple and predictive supersymmetric model implementing this scenario, where both the Higgsino and dark matter obtain masses from the same source of TeV-scale spontaneous symmetry breaking.

We present a lattice calculation of the electromagnetic form factor of the pion obtained using the tree-level Symanzik improved gauge action with two flavors of dynamical twisted Wilson quarks. The simulated pion masses range approximately from 260 to 580 MeV, and the lattice box sizes are chosen in order to guarantee that $M_{\pi }L\gtrsim 4$. Accurate results for the form factor are obtained using all-to-all quark propagators evaluated by a stochastic procedure. The momentum dependence of the pion form factor is investigated up to values of the squared four-momentum transfer $Q^2\simeq 0.8{\mathrm{GeV}}^2$ and, thanks to the use of twisted boundary conditions, down to $Q^2\simeq 0.05{\mathrm{GeV}}^2$. Volume and discretization effects on the form factor appear to be within the statistical errors. Our results for the pion mass, decay constant and form factor are analyzed using (continuum) chiral perturbation theory at next-to-next-to-leading order. The extrapolated value of the pion charge radius is $⟨r^2{⟩}^{\mathrm{phys}}=0.456\pm {0.030}_{\mathrm{stat}}\pm {0.024}_{\mathrm{syst}}$ in nice agreement with the experimental result. The extrapolated values of the pion form factor agree very well with the experimental data up to $Q^2\simeq 0.8{\mathrm{GeV}}^2$ within uncertainties which become competitive with the experimental errors for $Q^2\gtrsim 0.3{\mathrm{GeV}}^2$. The relevant low-energy constants appearing in the chiral expansion of the pion form factor are extracted from our lattice data, which come essentially from a single lattice spacing, adding the experimental value of the pion scalar radius in the fitting procedure. Our findings are in nice agreement with the available results of chiral perturbation theory analyses of $\pi -\pi$ scattering data as well as with other analyses of our collaboration.

We present constraints on the angle $\gamma$ of the unitarity triangle with a Dalitz analysis of neutral $D$ decays to $K_S{\pi }^{+}{\pi }^{-}$ from the processes $B^0\to {\overline{D}}^0{K}^{*0}$ (${\overline{B}}^0\to D^0{\overline{K}}^{*0}$) and $B^0\to D^0{K}^{*0}$ (${\overline{B}}^0\to {\overline{D}}^0{\overline{K}}^{*0}$) with $K^{*0}\to K^{+}{\pi }^{-}$ (${\overline{K}}^{*0}\to K^{-}{\pi }^{+}$). Using a sample of $371\times {10}^6$ $B\overline{B}$ pairs collected with the BABAR detector at PEP-II, we constrain the angle $\gamma$ as a function of $r_S$, the magnitude of the average ratio between $b\to u$ and $b\to c$ amplitudes.

The booster neutrino experiment (MiniBooNE) searches for ${\nu }_{\mu }\to {\nu }_e$ oscillations using the $\mathcal{O}(1\mathrm{GeV})$ neutrino beam produced by the booster synchrotron at the Fermi National Accelerator Laboratory). The booster delivers protons with 8 GeV kinetic energy ($8.89\mathrm{GeV}/c$ momentum) to a beryllium target, producing neutrinos from the decay of secondary particles in the beam line. We describe the Monte Carlo simulation methods used to estimate the flux of neutrinos from the beam line incident on the MiniBooNE detector for both polarities of the focusing horn. The simulation uses the Geant4 framework for propagating particles, accounting for electromagnetic processes and hadronic interactions in the beam line materials, as well as the decay of particles. The absolute double differential cross sections of pion and kaon production in the simulation have been tuned to match external measurements, as have the hadronic cross sections for nucleons and pions. The statistical precision of the flux predictions is enhanced through reweighting and resampling techniques. Systematic errors in the flux estimation have been determined by varying parameters within their uncertainties, accounting for correlations where appropriate.

Vacuum energy in quantum field theory, being the sum of zero-point energies of all field modes, is formally infinite but yet, after regularization or renormalization, can give rise to finite observable effects. One way of understanding how these effects arise is to compute the vacuum energy in an idealized system such as a large cavity divided into disjoint regions by pistons. In this paper, this type of calculation is carried out for situations where the potential affecting a field is not the same in all regions of the cavity. It is shown that the observable parts of the vacuum energy in such potentials do not fall off to zero as the region where the potential is nontrivial becomes large. This unusual behavior might be interesting for tests involving quantum vacuum effects and for studies on the relation between vacuum energy in quantum field theory and geometry.