Applying the effective Hamilton for $b\to s{l}^{+}{l}^{-}$, $(l=e,\mu )$ in the framework of the minimal supersymmetric extension of the standard model with local $B-L$ gauge symmetry, we investigate branching ratios and forward-backward asymmetries of rare decay $B\to X_S{l}^{+}{l}^{-}$ in low and high $q^2$ regions, respectively. In addition, we also study the $CP$ asymmetries depending on new $CP$ phases from soft breaking terms in low and high $q^2$ regions. Assuming that the soft breaking terms of the model induce new sources for flavor-changing neutral currents and CP violations, the numerical analyses of the supersymmetric contributions to the branching ratios, forward-backward and $CP$ asymmetries of $B\to X_S{l}^{+}{l}^{-}$ are presented in low and high $q^2$ regions, respectively.

Contributions of a spin-0 axionlike particle (ALP) to lepton dipole moments, $g-2$ and EDMs are examined. Barr-Zee and light-by-light loop effects from a light pseudoscalar ALP are found to be capable of resolving the longstanding muon $g-2$ discrepancy at the expense of relatively large $\mathrm{ALP}\text{−}\gamma \gamma$ couplings. The compatibility of such large couplings with direct experimental constraints and perturbative unitarity bounds is discussed. Future tests of such a scenario are described. For $CP$-violating ALP couplings, the electron EDM is found to probe much smaller, theoretically more easily accommodated ALP interactions. Future planned improvement in electron EDM searches is advocated as a way to not only significantly constrain ALP parameters, but also potentially unveil a new source of $CP$ violation which could have far-reaching ramifications.

Motivated by our limited knowledge of the Higgs couplings to the first two generation fermions, we analyze the collider phenomenology of a class of two Higgs doublet models (2HDMs) with a nonstandard Yukawa sector. One Higgs doublet is mainly responsible for the masses of the weak gauge bosons and the third-generation fermions, while the second Higgs doublet provides mass for the lighter fermion generations. The characteristic collider signatures of this setup differ significantly from well-studied 2HDMs with natural flavor conservation, flavor alignment, or minimal flavor violation. New production mechanisms for the heavy scalar, pseudoscalar, and charged Higgs involving second-generation quarks can become dominant. The most interesting decay modes include $H/A\to cc,tc,\mu \mu ,\tau \mu$ and $H^{\pm }\to cb,cs,\mu \nu$. Searches for low-mass dimuon resonances are currently among the best probes of the heavy Higgs bosons in this setup.

We study $\mathrm{\Lambda }$ baryons of spin-parity ${\frac{1}{2}}^{\pm }$ with either a strange or charm valence quark in full $2+1$ flavor lattice QCD. Multiple $SU(3)$ singlet and octet operators are employed to generate the desired single baryon states on the lattice. Via the variational method, the couplings of these states to the different operators provide information about the flavor structure of the $\mathrm{\Lambda }$ baryons. We make use of the gauge configurations of the PACS-CS Collaboration and chirally extrapolate the results for the masses and $SU(3)$ flavor components to the physical point. We furthermore gradually change the hopping parameter of the heaviest quark from strange to charm to study how the properties of the $\mathrm{\Lambda }$ baryons evolve as a function of the heavy quark mass. It is found that the baryon energy levels increase almost linearly with the quark mass. Meanwhile, the flavor structure of most of the states remains stable, with the exception of the lowest ${\frac{1}{2}}^{-}$ state, which changes from a flavor singlet $\mathrm{\Lambda }$ to a ${\mathrm{\Lambda }}_c$ state with singlet and octet components of comparable size. Finally, we discuss whether our findings can be interpreted with the help of a simple quark model and find that the negative-parity ${\mathrm{\Lambda }}_c$ states can be naturally explained as diquark excitations of the light $u$ and $d$ quarks. On the other hand, the quark-model picture does not appear to be adequate for the negative-parity $\mathrm{\Lambda }$ states, suggesting the importance of other degrees of freedom to describe them.

The drag and diffusion coefficients of heavy baryons (${\mathrm{\Lambda }}_c$ and ${\mathrm{\Lambda }}_b$) in the hadronic phase created in the latter stage of the heavy-ion collisions at RHIC and LHC energies have been evaluated recently. In this work we compute some experimental observables, such as the nuclear suppression factor $R_{AA}$ and the elliptic flow $v_2$ of heavy baryons at RHIC and LHC energies, highlighting the role of the hadronic phase contribution to these observables, which are going to be measured at Run 3 of LHC. For the time evolution of the heavy quarks in the quark and gluon plasma (QGP) and heavy baryons in the hadronic phase, we use the Langevin dynamics. For the hadronization of the heavy quarks to heavy baryons we employ Peterson fragmentation functions. We observe a strong suppression of both the ${\mathrm{\Lambda }}_c$ and ${\mathrm{\Lambda }}_b$. We find that the hadronic medium has a sizable impact on the heavy-baryon elliptic flow whereas the impact of hadronic medium rescattering is almost unnoticeable on the nuclear suppression factor. We evaluate the ${\mathrm{\Lambda }}_c/D$ ratio at RHIC and LHC. We find that the ${\mathrm{\Lambda }}_c/D$ ratio remains unaffected due to the hadronic phase rescattering which enables it as a nobel probe of QGP phase dynamics along with its hadronization.

We present an improved determination of the up- and down-quark distributions in the proton using recent data on charged lepton asymmetries from $W^{\pm }$ gauge-boson production at the LHC and Tevatron. The analysis is performed in the framework of a global fit of parton distribution functions. The fit results are consistent with a nonzero isospin asymmetry of the sea, $x(\overline{d}-\overline{u})$, at small values of Bjorken $x\sim {10}^{-4}$ indicating a delayed onset of the Regge asymptotics of a vanishing $(\overline{d}-\overline{u})$-asymmetry at small $x$. We compare with up- and down-quark distributions available in the literature and provide accurate predictions for the production of single top-quarks at the LHC, a process which can serve as a standard candle for the light quark flavor content of the proton.

We discuss charm quark/antiquark and charmed meson production in association with one extra jet (gluon, quark, antiquark) at the LHC. The calculations are performed both in collinear and $k_T$-factorization approaches. Different unintegrated gluon distribution functions are used in the $k_T$-factorization approach. Several predictions for the LHC are presented. We show distributions in rapidity and transverse momenta of $c/\overline{c}$ (or charmed mesons) and the associated jet as well as some two-dimensional observables. Interesting correlation effects are predicted, e.g., in azimuthal angles ${\phi }_{c\overline{c}}$ and ${\phi }_{c-\mathrm{jet}}$. We have also discussed a relation of the $2\to 2$ and $2\to 3$ partonic calculations in the region of large transverse momenta of charm quarks/antiquarks as well as the similarity of the next-to-leading order collinear approach and the $k_T$-factorization approach with the Kimber-Martin-Ryskin unintegrated parton distribution functions. Integrated cross sections for $D^0+\mathrm{jet}$ production for ATLAS detector acceptance and for different cuts on jet transverse momenta are also presented.

Analytical functions for the propagators of QCD, including a set of chiral quarks, are derived by a one-loop massive expansion in the Landau gauge, deep in the infrared. By analytic continuation, the spectral functions are studied in Minkowski space, yielding a direct proof of positivity violation and confinement from first principles. The dynamical breaking of chiral symmetry is described on the same footing of gluon mass generation, providing a unified picture. While dealing with the exact Lagrangian, the expansion is based on massive free-particle propagators, is safe in the infrared and is equivalent to the standard perturbation theory in the UV. By dimensional regularization, all diverging mass terms cancel exactly without including mass counterterms that would spoil the gauge and chiral symmetry of the Lagrangian. Universal scaling properties are predicted for the inverse dressing functions and shown to be satisfied by the lattice data. Complex conjugated poles are found for the gluon propagator, in agreement with the i-particle scenario.

Hadronic decays of radially excited $2D$ $D(2{{}^{3}D}_1)$, $D(2{{}^{3}D}_3)$, $D(2D_2)$, and $D(2D_2^{\prime })$ have been studied in a ${}^3{P}_0$ model. All Okubo-Zweig-Iizuka–allowed decay channels of these $2D$ $D$ resonances have been given, and relevant decay widths have been calculated. $D(2550)$, $D^{*}(2600)$, $D(2750)$, $D_1^{*}(2760)$, and $D_3^{*}(2760)$ can be produced in hadronic decays of $D(2{{}^{3}D}_1)$, $D(2{{}^{3}D}_3)$, $D(2D_2)$, and $D(2D_2^{\prime })$. In different assignments, hadronic decay widths and some relevant ratios from the $2D$ $D$ resonances to $D(2550)$, $D^{*}(2600)$, $D(2750)$, $D_1^{*}(2760)$, or $D_3^{*}(2760)$ final states have been predicted, which may provide more information to identify these resonances in forthcoming experiments.

In the twin Higgs model, the Higgs boson mass is protected by a ${\mathbb{Z}}_2$ symmetry. The ${\mathbb{Z}}_2$ symmetry needs to be broken either explicitly or spontaneously to obtain misalignment between electroweak and new physics vacua. We propose a novel ${\mathbb{Z}}_2$ breaking mechanism, in which the ${\mathbb{Z}}_2$ is spontaneously broken by radiative corrections to the Higgs potential. Two twin Higgses with different vacua are needed, and vacuum misalignment is realized by opposite but comparable contributions from gauge and Yukawa interactions to the potential. Because of fully radiative symmetry breaking, the Higgs sector is completely determined by twin Higgs vacuum, Yukawa and gauge couplings. There are eight pseudo-Goldstone bosons: the Higgs boson, inert doublet Higgs, and three twin scalars. We show the 125 GeV Higgs mass and constraints from Higgs coupling measurements could be satisfied.

We calculate the next-to-next-to-leading-order perturbative corrections to $P$-wave quarkonia annihilation decay to two photons, in the framework of nonrelativistic QCD factorization. The order-${\alpha }_s^2$ short-distance coefficients associated with each helicity amplitude are presented in a semianalytic form, including the “light-by-light” contributions. With sizable next-to-next-to-leading-order corrections, we find a disquieting discrepancy when confronting our state-of-the-art predictions with the latest BESIII measurements, which especially fail to account for the measured ${\chi }_{c2}\to \gamma \gamma$ width. Incorporating the effects of spin-dependent forces would even exacerbate the situation, since it lifts the degeneracy between the nonperturbative nonrelativistic QCD matrix elements of ${\chi }_{c0}$ and ${\chi }_{c2}$ toward the wrong direction. We also present the order-${\alpha }_s^2$ predictions to ${\chi }_{b0,2}\to \gamma \gamma$, which await the future experimental test.

We construct the six-point, next-to-maximally-helicity-violating one-loop amplitude in $\mathcal{N}=4$ supergravity using unitarity and recursion. The use of recursion requires the introduction of rational descendants of the cut-constructible pieces of the amplitude and the computation of the nonstandard factorization terms arising from the loop integrals.

We construct static and spherically symmetric generalizations of the Schwarzschild- and Reissner-Nordström-(anti–)de Sitter [RN-(A)dS] black-hole solutions in four-dimensional Einsteinian cubic gravity (ECG). The solutions are characterized by a single function which satisfies a nonlinear second-order differential equation. Interestingly, we are able to compute independently the Hawking temperature $T$, the Wald entropy $\mathsf{S}$ and the Abbott-Deser mass $M$ of the solutions analytically as functions of the horizon radius and the ECG coupling constant $\lambda$. Using these we show that the first law of black-hole mechanics is exactly satisfied. Some of the solutions have positive specific heat, which makes them thermodynamically stable, even in the uncharged and asymptotically flat case. Further, we claim that, up to cubic order in curvature, ECG is the most general four-dimensional theory of gravity which allows for nontrivial generalizations of Schwarzschild- and RN-(A)dS characterized by a single function which reduce to the usual Einstein gravity solutions when the corresponding higher-order couplings are set to zero.

Simplicity constraints play a crucial role in the construction of spin foam models, yet their effective behavior on larger scales is scarcely explored. In this article we introduce intertwiner and spin net models for the quantum group $\mathrm{SU}(2{)}_k\times \mathrm{SU}(2{)}_k$, which implement the simplicity constraints analogous to four-dimensional Euclidean spin foam models, namely the Barrett-Crane (BC) and the Engle-Pereira-Rovelli-Livine/Freidel-Krasnov (EPRL/FK) model. These models are numerically coarse grained via tensor network renormalization, allowing us to trace the flow of simplicity constraints to larger scales. In order to perform these simulations we have substantially adapted tensor network algorithms, which we discuss in detail as they can be of use in other contexts. The BC and the EPRL/FK model behave very differently under coarse graining: While the unique BC intertwiner model is a fixed point and therefore constitutes a two-dimensional topological phase, BC spin net models flow away from the initial simplicity constraints and converge to several different topological phases. Most of these phases correspond to decoupling spin foam vertices; however we find also a new phase in which this is not the case, and in which a nontrivial version of the simplicity constraints holds. The coarse graining flow of the BC spin net models indicates furthermore that the transitions between these phases are not of second order. The EPRL/FK model by contrast reveals a far more intricate and complex dynamics. We observe an immediate flow away from the original simplicity constraints; however, with the truncation employed here, the models generically do not converge to a fixed point. The results show that the imposition of simplicity constraints can indeed lead to interesting and also very complex dynamics. Thus we need to further develop coarse graining tools to efficiently study the large scale behavior of spin foam models, in particular for the EPRL/FK model.

We point out that in the standard model there is meaningful quark mixing even in the extreme chiral (EC) limit, where only the third generation of quarks acquires mass. This mixing is in general expected to be of order 1 and the fact that $|V_{13}{|}^2+|V_{23}{|}^2\approx 1.6\times 10^{-3}$ implies a novel fine-tuning problem in the SM which we point out for the first time. We propose a possible way of avoiding this fine-tuning by introducing a symmetry $S$ which leads to $V_{\mathrm{CKM}}=\mathbb{1}$, with only the third generation of quarks acquiring mass. We consider two scenarios for generating the mass of the first two quark generations and full quark mixing based on the assumption that the masses of the first two quark families are not generated by the standard Higgs. One consists of the introduction of a second Higgs doublet which is neutral under $S$. The second scenario consists of assuming new physics at a high energy scale, contributing to the masses of light quark generations, in an effective field theory approach. This last scenario leads to couplings of the Higgs particle to $s\overline{s}$ and $c\overline{c}$ which are significantly enhanced with respect to those of the SM. In both schemes, one has scalar-mediated flavor-changing neutral currents which are naturally suppressed. Flavor-violating top decays are predicted in the second scenario at the level $\mathrm{Br}(t\to hc)\ge 5\times 10^{-5}$.

Chiral symmetry restoration high in the hadron spectra is expected but it remains to be confirmed both in lattice QCD computations and in experiments. Recently, a theorem was derived, relating chiral symmetry restoration high in the hadron spectra to the spontaneous generation of the dynamical quark mass in QCD. We refine the theorem in the case of static-light mesons. Utilizing chiral quark model computations and lattice QCD results for the spectrum of mesons composed by a static antiquark and a light quark, we explore chiral symmetry restoration in the spectrum and the quark running mass $m(k)$.

Results are presented from searches for $R$-parity-violating supersymmetry in events produced in $pp$ collisions at $\sqrt{s}=8\mathrm{TeV}$ at the LHC. Final states with 0, 1, 2, or multiple leptons are considered independently. The analysis is performed on data collected by the CMS experiment corresponding to an integrated luminosity of $19.5{\mathrm{fb}}^{-1}$. No excesses of events above the standard model expectations are observed, and 95% confidence level limits are set on supersymmetric particle masses and production cross sections. The results are interpreted in models featuring $R$-parity-violating decays of the lightest supersymmetric particle, which in the studied scenarios can be either the gluino, a bottom squark, or a neutralino. In a gluino pair production model with baryon number violation, gluinos with a mass less than 0.98 and 1.03 TeV are excluded, by analyses in a fully hadronic and one-lepton final state, respectively. An analysis in a dilepton final state is used to exclude bottom squarks with masses less than 307 GeV in a model considering bottom squark pair production. Multilepton final states are considered in the context of either strong or electroweak production of superpartners and are used to set limits on the masses of the lightest supersymmetric particles. These limits range from 300 to 900 GeV in models with leptonic and up to approximately 700 GeV in models with semileptonic $R$-parity-violating couplings.

We report the double-helicity asymmetry, $A_{LL}^{J/\psi }$, in inclusive $J/\psi$ production at forward rapidity as a function of transverse momentum $p_T$ and rapidity $|y|$. The data analyzed were taken during $\sqrt{s}=510\mathrm{GeV}$ longitudinally polarized $p+p$ collisions at the Relativistic Heavy Ion Collider in the 2013 run using the PHENIX detector. At this collision energy, $J/\psi$ particles are predominantly produced through gluon-gluon scatterings, thus $A_{LL}^{J/\psi }$ is sensitive to the gluon polarization inside the proton. We measured $A_{LL}^{J/\psi }$ by detecting the decay daughter muon pairs ${\mu }^{+}{\mu }^{-}$ within the PHENIX muon spectrometers in the rapidity range $1.2<|y|<2.2$. In this kinematic range, we measured the $A_{LL}^{J/\psi }$ to be $0.012\pm 0.010$ (stat) $\pm 0.003$ (syst). The $A_{LL}^{J/\psi }$ can be expressed to be proportional to the product of the gluon polarization distributions at two distinct ranges of Bjorken $x$: one at moderate range $x\approx 5\times {10}^{-2}$ where recent data of jet and ${\pi }^0$ double helicity spin asymmetries have shown evidence for significant gluon polarization, and the other one covering the poorly known small-$x$ region $x\approx 2\times {10}^{-3}$. Thus our new results could be used to further constrain the gluon polarization for $x<5\times {10}^{-2}$.

We study asymptotically Lifshitz solutions with critical exponent $z\ne 1$ in Hořava gravity in three and four spacetime dimensions. For $z=2$ and $z=3/2$, we find a novel class of numerical solutions with regular universal horizon but that are characterized by nonanalytic behavior near infinity. In the interior, inside the universal horizon, the unit timelike vector field associated with the preferred time foliation exhibits oscillatory behavior, qualitatively similar to that found earlier in asymptotically flat solutions. For $z>2$, no solutions of this type appear to exist. We comment on potential applications to holographic Lifshitz dualities.