We investigate the potential of multivariate techniques to improve the LHC search for invisible Higgs decays in weak boson fusion. We find that in the coming runs the LHC will be able to probe an invisible Higgs width of 28% within a year and 3.5% during a high luminosity run. A significant improvement over these estimates requires an analysis of QCD radiation patterns down to 10 GeV. Such an analysis can improve the reach at the high luminosity run to 2%. Throughout our analysis, we employ a conservative, data-driven background determination.

Through the spin rearrangement scheme in the heavy quark limit, we have performed a comprehensive investigation of the decay pattern and production mechanism of the hidden beauty dimeson states, which are either composed of a $P$-wave bottom meson and an $S$-wave bottom meson or two $S$-wave bottom mesons. We further extend the corresponding formula to discuss the decay behavior of some charmonium-like states by combining the experimental information with our numerical results. The typical ratios presented in this work can be measured by future experiments like BESIII, Belle, LHCb and the forthcoming BelleII, which shall provide important clues to the inner structures of the exotic states.

We investigate chiral symmetry breaking and strong charge parity ($CP$) violation effects on the phase diagram of strongly interacting matter in the presence of a constant magnetic field. The effects of a magnetic field and strong $CP$ violating term on the phase structure at finite temperature and density are studied within a three flavor Nambu-Jona-Lasinio model including the Kobayashi-Maskawa-t’Hooft determinant term. This is investigated using an explicit variational ansatz for ground state with quark-antiquark pairs leading to condensates both in scalar and pseudoscalar channels. A magnetic field enhances the condensate in both the channels. Inverse magnetic catalysis for $CP$ transition at finite chemical potential is seen for zero temperature and for small magnetic fields. The $CP$ transition becomes first order at finite baryon chemical potential and could be relevant for generating $CP$-odd metastable domains in heavy ion collision experiments.

An extensive model-independent analysis of $B\to DD$ decays is carried out employing $SU(3)$ flavor symmetry, including symmetry-breaking corrections. Several theoretically clean observables are identified which allow for testing the standard model. These include the known time-dependent $CP$ asymmetries, the penguin pollution of which can be controlled in this framework, but notably also quasi-isospin relations which are experimentally well accessible and unaffected by symmetry-breaking corrections. Theoretical assumptions can be kept to a minimum and controlled by additional sum rules. Available data are used in global fits to predict the branching ratio for the $B^0\to D_s^{+}{D}_s^{-}$ decay as well as several $CP$ asymmetries which have not been measured so far, and future prospects are analyzed.

Recently a lot of progress has been made towards a full classification of new physics effects in Higgs observables by means of effective dimension-six operators. Specifically, Higgs production in association with a high transverse momentum jet has been suggested as a way to discriminate between operators that modify the Higgs-top coupling ($O_t$) and operators that induce an effective Higgs-gluon coupling ($O_g$)—a distinction that is hard to achieve with signal strength measurements alone. With this article we would like to draw attention to another source of new physics in $\mathrm{Higgs}+\mathrm{jet}$ observables: the triple gluon operator $O_{3g}$ (consisting of three factors of the gluon field strength tensor). We compute the distortions of kinematic distributions in $\mathrm{Higgs}+\mathrm{jet}$ production at a 14 TeV LHC due to $O_{3g}$ and compare them with the distortions due to $O_t$ and $O_g$. We find that the transverse momentum distributions alone cannot discriminate between $O_{3g}$ and $O_g$ if the coefficient of the operator $O_t$ treated as an unknown parameter. We further show that the jet rapidity and the difference between the Higgs and jet rapidity are well suited to remove this new degeneracy. Using rough estimates for the expected bounds we find that allowed distortions in kinematic distributions due to $O_g$ are of similar size as those due to $O_{3g}$. We conclude that a full analysis of new physics in $\mathrm{Higgs}+\mathrm{jet}$ observables must take the contributions from $O_{3g}$ into account.

We obtain exact solutions of the ($2+1$)-dimensional Dirac oscillator in a homogeneous magnetic field within a minimal-length ($\mathrm{\Delta }{x}_0=\hslash \sqrt{\beta }$) or generalized uncertainty principle scenario. This system in ordinary quantum mechanics has a single left-right chiral quantum phase transition (QPT). We show that a nonzero minimal length turns on an infinite number of quantum phase transitions which accumulate towards the known QPT when $\beta \to 0$. It is also shown that the presence of the minimal length modifies the degeneracy of the states and that in this case there exists a new class of states which do not survive in the ordinary quantum mechanics limit $\beta \to 0$.

We investigate the thermodynamics of hairy black holes in asymptotically anti–de Sitter (AdS) space, including backreaction. Resorting to the Euclidean path integral approach, we show that matter conformally coupled to Einstein gravity in five dimensions may exhibit a phase transition whose endpoint turns out to be a hairy black hole in ${\mathrm{AdS}}_5$ space. The scalar field configuration happens to be regular everywhere outside and on the horizon and behaves asymptotically in such a way that respects the AdS boundary conditions that are relevant for AdS/CFT. The theory presents other peculiar features in the ultraviolet, like the existence of black holes with arbitrarily low temperature in ${\mathrm{AdS}}_5$. This provides a simple setup in which the fully backreacting problem of a hair forming in AdS at a certain critical temperature can be solved analytically.

Using recently developed nonrelativistic numerical simulation code, we investigate the stability properties of compact astrophysical objects that may be formed due to the Bose-Einstein condensation of dark matter. Once the temperature of a boson gas is less than the critical temperature, a Bose-Einstein condensation process can always take place during the cosmic history of the Universe. Because of dark matter accretion, a Bose-Einstein condensed core can also be formed inside massive astrophysical objects such as neutron stars or white dwarfs, for example. Numerically solving the Gross-Pitaevskii-Poisson system of coupled differential equations, we demonstrate, with longer simulation runs, that within the computational limits of the simulation the objects we investigate are stable. Physical properties of a self-gravitating Bose-Einstein condensate are examined both in nonrotating and rotating cases.

Relativistic, spherically symmetric configurations consisting of a gravitating magnetized anisotropic fluid are studied. For such configurations, we obtain static equilibrium solutions with an axisymmetric, poloidal magnetic field produced by toroidal electric currents. The presence of such a field results in small deviations of the shape of the configuration from spherical symmetry. This in turn leads to the modification of an equation for the current and correspondingly to changes in the structure of the internal magnetic field for the systems supported by the anisotropic fluid, in contrast to the case of an isotropic fluid, where such deviations do not affect the magnetic field.

The Hawking temperature for the Schwarzschild black hole is divergent when the mass of the black hole vanishes; however, the corresponding geometry becomes the Minkowski spacetime whose intrinsic temperature is zero. In connection with this issue, we construct a nonsingular temperature which follows the Hawking temperature for the large black hole, while it vanishes when the black hole is completely evaporated. For the thermodynamics significances of this modified temperature, we calculate thermodynamic quantities and study phase transitions. It turns out that even the small black hole can be stable below a certain temperature, and the hot flat space is always metastable so that it decays into the stable small black hole or the stable large black hole.

We study the asymptotic scaling properties of domain wall networks with three different tensions in various cosmological epochs. We discuss the conditions under which a scale-invariant evolution of the network (which is well established for simpler walls) still applies and also consider the limiting case where defects are locally planar and the curvature is concentrated in the junctions. We present detailed quantitative predictions for scaling densities in various contexts, which should be testable by means of future high-resolution numerical simulations.

Sterile neutrinos in the mass range of a few keV are candidates for both cold and warm dark matter. An admixture of a heavy neutrino mass eigenstate to the electron neutrino would result in a minuscule distortion—a kink—in a $\beta$-decay spectrum. In this paper we show that a wavelet transform is a very powerful shape analysis method to detect this signature. For a tritium source strength, similar to what is expected from the KATRIN experiment, a statistical sensitivity to active-to-sterile neutrino mixing down to ${\sin }^2\theta =10^{-6}$ (90% C.L.) can be obtained after three years of measurement time. It is demonstrated that the wavelet approach is largely insensitive to systematic effects that result in smooth spectral modifications. To make full use of this analysis technique a high-resolution measurement (FWHM of $\sim 100\mathrm{eV}$) of the tritium $\beta$-decay spectrum is required.

We respond to the comments on my recent paper, Y. Giraldo [Phys. Rev. D 86, 093021 (2012)]. In their comments, they begin discussing a particular class of five-zero texture non-Fritzsch-like quark mass matrix, which was proposed by me, and question its validity. Then, they put in doubt the phases included in the unitary matrices used for diagonalizing the quark mass matrices, from which they claim that the $CP$ violating parameter ${\epsilon }_k$ obtained does not agree with the experimental value. Because of these comments, finally, they recommend being careful while analyzing the implications of weak basis transformations on textures. Other minor points are also discussed by them. In the following, I will show that the mentioned five-zero texture non-Fritzsch-like quark mass matrices are completely valid and generate all the physical quantities involved, including the $CP$ violating parameter ${\epsilon }_k$, for which is required the inclusion of phases in the unitary matrices used for diagonalizing the quark mass matrices in order to put the Cabibbo-Kobayashi-Maskawa matrix in standard form. These phases can be rotated away so they do not have any physical meaning. Finally, the relevance of the weak basis transformation is appreciated: it is complete and facilitates calculations, especially of texture zeros.

Recently, using specific weak basis transformations, Y. Giraldo [Phys. Rev. D 86, 093021 (2012)] constructed some texture 5 and 4 zero quark mass matrices and examined their compatibility with the quark mixing data. In this comment, we have reanalyzed these to bring forth certain important issues regarding their viability which need to be taken note of.

Introducing an arbitrary number of neutral Higgs bosons in the electroweak symmetry breaking sector, we derive a set of conditions among Higgs couplings which need to be satisfied to maintain the unitarity of the high energy scattering amplitudes of weak gauge bosons at the tree level (unitarity sum rules). It is shown that the unitarity sum rules require the tree level $\rho$ parameter to be 1, without explicitly invoking the custodial symmetry arguments. The one loop finiteness of the electroweak oblique corrections is automatically guaranteed once these unitarity sum rules are imposed among Higgs couplings. Severe constraints on the lightest Higgs coupling (125 GeV Higgs coupling) and the mass of the second lightest Higgs boson are obtained from the unitarity and the results of the electroweak precision tests (oblique parameter measurements). These results are compared with the effective theory of the light Higgs boson, and we find simple relationships between the mass of the second lightest Higgs boson in our framework and the ultraviolet cutoff in the effective theory framework.

We investigate the double spin asymmetries of pion production in semi-inclusive deep inelastic scattering with a longitudinal polarized beam off a transversely polarized proton target. Particularly, we consider the $\cos {\varphi }_S$ and $\cos (2{\varphi }_h-{\varphi }_S)$ modulations, which can be interpreted by the convolution of the twist-3 transverse momentum dependent distributions and twist-2 fragmentation functions. Three different origins are taken into account simultaneously for each asymmetry: the $g_T{D}_1$ term, the $e_T{H}_1^{\perp }$ term, and the $e_T^{\perp }{H}_1^{\perp }$ term in the $\cos {\varphi }_S$ asymmetry; and the $g_T^{\perp }{D}_1$ term, the $e_T{H}_1^{\perp }$ term, and the $e_T^{\perp }{H}_1^{\perp }$ term in the $\cos (2{\varphi }_h-{\varphi }_S)$ asymmetry. We calculate the four twist-3 distributions $g_T(x,{\mathit{k}}_T^2)$, $g_T^{\perp }(x,{\mathit{k}}_T^2)$, $e_T(x,{\mathit{k}}_T^2)$, and $e_T^{\perp }(x,{\mathit{k}}_T^2)$ in a spectator-diquark model including vector diquarks. Then we predict the two corresponding asymmetries for charged and neutral pions at the kinematics of HERMES, JLab, and COMPASS for the first time. The numerical estimates indicate that the two different angular-dependence asymmetries are sizable by several percent at HERMES and JLab, and the $\cos {\varphi }_S$ asymmetry has a strong dependence on the Bjorken $x$. Our predictions also show that the dominant contribution to the $\cos {\varphi }_S$ asymmetry comes from the $g_T{D}_1$ term, while the $g_T^{\perp }{D}_1$ term gives the main contribution to the $\cos (2{\varphi }_h-{\varphi }_S)$ asymmetry; the other two $T$-odd terms almost give negligible contributions. In particular, the $\cos (2{\varphi }_h-{\varphi }_S)$ asymmetry provides a unique opportunity to probe the distribution $g_T^{\perp }$.

We discuss the $\mathcal{O}({\alpha }_s)$ supersymmetric QCD corrections to neutralino-stop coannihilation into a top quark and a gluon in the minimal supersymmetric Standard Model (MSSM). This particular channel can be numerically important in wide ranges of the MSSM parameter space with rather light stops. We discuss technical details such as the renormalization scheme and the phase-space slicing method with two cutoffs. We also comment on improvements with respect to earlier works on the given process. Further, we study for the first time the phenomenologically very interesting interplay of neutralino-stop coannihilation with neutralino-pair annihilation into quark pairs taking the full next-to-leading order SUSY-QCD corrections into account. We demonstrate that the numerical impact of these corrections on the total (co)annihilation cross section and finally on the theoretically predicted neutralino relic density is significant.

We study the semileptonic tree-level $B\to \overline{D}$ transition in the framework of QCD sum rules in a nuclear medium. In particular, we calculate the in-medium form factors entering the transition matrix elements defining this decay channel. It is found that the interactions of the participating particles with the medium lead to a considerable suppression in the branching ratio compared to the vacuum.

The nature of chiral phase transition of massless two flavor QCD depends on the fate of flavor singlet axial symmetry $U_A(1)$ at the critical temperature ($T_c$). Assuming that a finite $U_A(1)$ breaking remains at $T_c$, the corresponding three dimensional effective theory is composed of four massless and four massive scalar fields. We study the renormalization group flow of the effective theory in the $\epsilon$-expansion, using a mass dependent renormalization scheme, and determine the region of the attractive basin flowing into the $O(4)$ fixed point with a focus on its dependence on the size of the $U_A(1)$ breaking. The result is discussed from a perspective of the decoupling of massive fields. It is pointed out that, although the effective theory inside the attractive basin eventually reaches the $O(4)$ fixed point, the approaching rate, one of the universal exponents, is different from that of the standard $O(4)$ model. We present the reason for this peculiarity, and propose a novel possibility for chiral phase transition in two-flavor QCD.

We discuss the quark and gluon condensates in the presence of a rectangular Wilson loop using the QCD instanton vacuum with three light dynamical quarks. The scalar quark condensate is found to decrease while the gluon condensate increases. We also derive the static potential between two QCD dipoles and show that it is attractive but short ranged at large distances. Its relevance to static QCD string interactions is discussed.