A quirk propagating through a detector is subject to the Lorentz force, a new confining gauge force, and the frictional force from ionization energy loss. At the LHC, it was found that the monojet search and the coplanar search were able to constrain such a quirk signal. Inspired by the coplanar search proposed by Knapen et al. [Phys. Rev. D 96, 115015 (2017)], we develop a new search that also utilizes the information of the relatively large ionization energy loss inside the tracker. Our algorithm has improved efficiency in finding quirk signals with a wide oscillation amplitude. Because of our trigger strategy, the $Z(\to \nu \nu )+\text{jets}$ process overlaid by pileup events is the dominant background. We find that the $\sim 100{\mathrm{fb}}^{-1}$ dataset at the LHC will be able to probe the colored fermion (scalar) quirks with masses up to 2.1 (1.1) TeV and the color neutral fermion (scalar) quirks with masses up to 450 (150) GeV, respectively.

Baryons with a heavy c-quark or a heavy b-quark and also two c-quarks have been discovered. These states are expected in QCD and therefore provide a test for the theory. There should be double beauty baryons, and also an intriguing possibility that baryons ${\mathbf{B}}_{bc}$ with a c-quark, a b-quark. These states are yet to be discovered. The main decay modes of ${\mathbf{B}}_{bc}$ are expected to be weak processes from theoretical understanding of their mass spectrum. These decay modes can provide crucial information about these heavy baryons ${\mathbf{B}}_{bc}$. We analyze two body hadronic weak decays for ${\mathbf{B}}_{bc}$ using $SU(3)$ flavor symmetry. Any one of the $c$ and $b$ decays will induce ${\mathbf{B}}_{bc}$ to decay. We find that the Cabibbo allowed decays ${\mathbf{B}}_{bc}\to {\mathbf{B}}_b+M$ due to $c\to su\overline{d}$ can be crucial for exploration. The LHC may have the sensitivity to discover such decays. Other ${\mathbf{B}}_{bc}$ decays due to $b\to c{q}^{\prime }\overline{q}$ are subleading. Several relations among branching ratios are obtained which can be used to test $SU(3)$ flavor symmetry.

We have considered a model [E. Ma and D. Wegman, Phys. Rev. Lett. 107, 061803 (2011)], where masses and a mixing pattern for neutrinos are governed by six Higgs triplets and $A_4$ symmetry. In this model we have applied a certain diagonalization procedure through which we have shown that neutrino masses can have both normal or inverted hierarchy. We have also shown that current neutrino oscillation data can be explained in this model.

We study the constraints on $t\to u$ flavor changing neutral Higgs coupling and how it may be explored further at the LHC. In the general two Higgs doublet model, such transitions can be induced by a nonzero ${\rho }_{tu}$ Yukawa coupling. We show that such couplings can be constrained by existing searches at the LHC for $m_H$, $m_A$, and $m_{H^{+}}$ in the sub-TeV range, where $H$, $A$, and $H^{+}$ are the exotic $CP$-even, $CP$-odd, and charged scalars. We find that a dedicated $ug\to tH/tA\to tt\overline{u}$ search can probe the available parameter space of ${\rho }_{tu}$ down to a few percent level for $200\mathrm{GeV}\lesssim m_H$, $m_A\lesssim 600\mathrm{GeV}$, with discovery possible at high luminosity. Effects of how other extra top Yukawa couplings, such as ${\rho }_{tc}$ and ${\rho }_{tt}$, dilute the sensitivity of the ${\rho }_{tu}$ probe are discussed.

Recently, the KOTO experiment reported their new preliminary result of searching for the decay $K_L\to {\pi }^0\nu \overline{\nu }$. Three candidate events were observed in the signal region, which exceed significantly the expectation based on the standard model. On the other hand, the new NA62 and previous BNL-E949 experiments yielded a consistent result and confirmed the standard model prediction in the charged meson decay $K^{+}\to {\pi }^{+}\nu \overline{\nu }$. Furthermore, the two decays are bound by a well-motivated relation from an analysis of isospin symmetry that is hard to break by the new physics of heavy particles. In this work, we study the issue by a systematic effective field theory approach with three of the simplest scenarios, in which the $K_L$ may decay into a new light neutral particle $X$, i.e., $K_L\to {\pi }^{0}X$, $K_L\to \gamma \gamma X$, or $K_L\to {\pi }^{0}XX$. We assess the feasibility of the scenarios by simulations and by incorporating constraints coming from NA62 and other relevant experiments. Our main conclusion is that the scenario $K\to \pi XX$ for a long-lived scalar $X$ seems more credible than the other two when combining distributions and other experimental constraints while the region below the KOTO’s blind box provides a good detection environment to search for all three scenarios for a relatively heavy $X$.

Static quark-antiquark states in QCD, at finite quark separation, have a spectrum of metastable states corresponding to stringlike excitations of the gauge field. In this article I suggest that there may also exist an excitation spectrum of heavy fermions in some gauge Higgs theories deep in the Higgs phase. In this situation there are no color electric flux tubes connecting quarks with antiquarks. There may, nonetheless, exist stable excitations of the bosonic fields surrounding an isolated fermion, below the particle production threshold. I present numerical evidence indicating the existence of such excitations in an SU(3) gauge Higgs theory, with the scalar field in the fundamental representation of the gauge group.

We investigate the advantages of machine learning techniques to recognize the dynamics of topological objects in quantum field theories. We consider the compact U(1) gauge theory in three spacetime dimensions as the simplest example of a theory that exhibits confinement and mass gap phenomena generated by monopoles. We train a neural network with a generated set of monopole configurations to distinguish between confinement and deconfinement phases, from which it is possible to determine the deconfinement transition point, and to predict several observables. The model uses a supervised learning approach and treats the monopole configurations as three-dimensional images (holograms). We show that the model can determine the transition temperature with accuracy, which depends on the criteria implemented in the algorithm. More importantly, we train the neural network with configurations from a single lattice size before making predictions for configurations from other lattice sizes, from which a reliable estimation of the critical temperatures is obtained.

The $a_0^0(980)-f_0(980)$ mixing is one of the most promising potential tools to learn about the nature of $a_0^0(980)$ and $f_0(980)$. Using the $f_0(980)-a_0^0(980)$ mixing intensity ${\xi }_{af}$ measured recently at the BESIII experiment, we calculate the branching ratio of the isospin violation decay $J/\psi \to \gamma {\eta }_c\to \gamma {\pi }^0{a}_0^0(1450)\to \gamma {\pi }^0{a}_0^0(980)f_0(500)\to \gamma {\pi }^0{f}_0(980)f_0(500)\to \gamma {\pi }^0{\pi }^{+}{\pi }^{-}{\pi }^{+}{\pi }^{-}$. The value of the branching ratio is found to be $O({10}^{-6})$, which can be observed with ${10}^{10}J/\psi$ events collected at the BESIII experiment. The narrow peak from the $f_0(980)-a_0^0(980)$ mixing in the ${\pi }^{+}{\pi }^{-}$ mass square spectrum can also be observed. In addition, we study the nonresonant decay $a_0^0(1450)\to f_0(980){\pi }^{+}{\pi }^{-}(\text{nonresonant})$, which is dominated by the $a_0^0(980)-f_0(980)$ mixing. We find that the nonresonant decay $a_0^0(1450)\to f_0(980){\pi }^{+}{\pi }^{-}$ and the decay $a_0^0(1450)\to f_0(980)f_0(500)$ can be combined to measure the mixing intensity ${\xi }_{af}$ in experiment. These decays are the perfect complement to the decay ${\chi }_{c1}\to f_0(980){\pi }^0\to {\pi }^{+}{\pi }^{-}{\pi }^0$, which had been observed at the BESIII experiment, the observations of which will make the measurement of the mixing intensity ${\xi }_{af}$ more precisely.

Motivated by the Belle Collaboration’s new observation of $Y(4626)$, we investigate the possibility of its configuration as a $P$-wave $[cs][\overline{c}\overline{s}]$ tetraquark state from QCD sum rules. Eventually, the extracted mass ${4.60}_{-0.19}^{+0.13}\mathrm{GeV}$ for the $P$-wave $cs$-scalar-diquark $\overline{c}\overline{s}$-scalar-antidiquark state agrees well with the experimental data of $Y(4626)$, which could support its interpretation as a $P$-wave scalar-scalar $[cs][\overline{c}\overline{s}]$ tetraquark state.

Charged particle multiplicities in proton-proton collisions measured in the LHCb detector at a center-of-mass energy of $\sqrt{s}=7\mathrm{TeV}$ in different windows of pseudorapidity, $\eta$, in the forward region of the vertex detector are studied by using different statistical distributions. Three distributions are compared with the data, and the moments of the distributions are calculated. The data constituting two sets, one of minimum bias events and another of hard QCD events, are analyzed. The distributions considered derive from different functional forms based on underlying interaction dynamics. The analysis complements the multiplicity analysis done by LHCb in terms of Monte Carlo event generators. The present analysis is from a different perspective, using statistical distributions.

Considering the strong field approximation we compute the hard thermal loop pressure at finite temperature and chemical potential of hot and dense deconfined QCD matter in the lowest Landau level in one-loop order. We consider the anisotropic pressure in the presence of the strong magnetic field i.e., longitudinal and transverse pressure parallel and perpendicular to the magnetic field direction. As a first effort we compute and discuss the anisotropic quark number susceptibility of deconfined QCD matter in the lowest Landau level. The longitudinal quark number susceptibility is found to increase with the temperature whereas the transverse one decreases with the temperature. We also compute the quark number susceptibility in the weak field approximation. We find that the thermomagnetic correction to the quark number susceptibility is very marginal in the weak field approximation.

The diffractive electro- or photoproduction of two mesons separated by a large rapidity gap gives access to generalized parton distributions (GPDs) in a very specific way. First, these reactions allow us to easily access the chiral-odd transversity quark GPDs by selecting one of the produced vector mesons to be transversely polarized. Second, they are only sensitive to the so-called Efremov-Radyushkin-Brodsky-Lepage region where GPDs are not much constrained by forward quark distributions. Third, the skewness parameter $\xi$ is not related to the Bjorken $x_{\mathrm{Bj}}$ variable, but to the size of the rapidity gap. We analyze different channels (${\rho }_L^0{\rho }_{L/T}$, ${\rho }_L^0{\omega }_{L/T}$ and ${\rho }_L^0\pi$ production) on nucleon and deuteron targets. The analysis is performed in the kinematical domain where a large momentum transfer from the photon to the diffractively produced vector meson introduces a hard scale (the virtuality of the exchanged hard Pomeron). This enables the description of the hadronic part of the process in the framework of collinear factorization of GPDs. We show that the unpolarized cross sections depend very much on the parametrizations of both chiral-even and chiral-odd quark distributions of the nucleon, as well as on the shape of the meson distribution amplitudes. The rates are shown to be in the range of the capacities of a future electron-ion collider.

Several methods exist to measure $CP$ violation observables related to the CKM unitarity triangle angle $\gamma$ using $B$ meson decays. These observables are different for every $B$ meson decay considered, although the information they contain on $\gamma$ is encoded in a similar way for all of them. This paper describes a strategy for a simultaneous measurement of $\gamma$ using several $B$ meson decays that takes into account possible correlations between them based on the methodologies described in [J. Garra Ticó, arXiv:1804.05597]. Sensitivity studies demonstrate that the simultaneous analysis of several $B$ meson decay modes results in smaller uncertainties and improved statistical behavior compared to a combination of standalone measurements.

Using $2.93{\mathrm{fb}}^{-1}$ of $e^{+}{e}^{-}$ collision data taken at a center-of-mass energy of 3.773 GeV by the BESIII detector at the BEPCII, we measure the branching fractions of the singly Cabibbo-suppressed decays $D\to \omega \pi \pi$ to be $\mathcal{B}(D^0\to \omega {\pi }^{+}{\pi }^{-})=(1.33\pm 0.16\pm 0.12)\times {10}^{-3}$ and $\mathcal{B}(D^{+}\to \omega {\pi }^{+}{\pi }^0)=(3.87\pm 0.83\pm 0.25)\times {10}^{-3}$, where the first uncertainties are statistical and the second ones systematic. The statistical significances are $12.9\sigma$ and $7.7\sigma$, respectively. The precision of $\mathcal{B}(D^0\to \omega {\pi }^{+}{\pi }^{-})$ is improved by a factor of 2.1 over prior measurements, and $\mathcal{B}(D^{+}\to \omega {\pi }^{+}{\pi }^0)$ is measured for the first time. No significant signal for $D^0\to \omega {\pi }^0{\pi }^0$ is observed, and the upper limit on the branching fraction is $\mathcal{B}(D^0\to \omega {\pi }^0{\pi }^0)<1.10\times {10}^{-3}$ at the 90% confidence level. The branching fractions of $D\to \eta \pi \pi$ are also measured and consistent with existing results.

The STEREO experiment is a very short baseline reactor antineutrino experiment. It is designed to test the hypothesis of light sterile neutrinos being the cause of a deficit of the observed antineutrino interaction rate at short baselines with respect to the predicted rate, known as the reactor antineutrino anomaly. The STEREO experiment measures the antineutrino energy spectrum in six identical detector cells covering baselines between 9 and 11 m from the compact core of the ILL research reactor. In this article, results from 179 days of reactor turned on and 235 days of reactor turned off are reported at a high degree of detail. The current results include improvements in the modelling of detector optical properties and the $\gamma$-cascade after neutron captures by gadolinium, the treatment of backgrounds, and the statistical method of the oscillation analysis. Using a direct comparison between antineutrino spectra of all cells, largely independent of any flux prediction, we find the data compatible with the null oscillation hypothesis. The best-fit point of the reactor antineutrino anomaly is rejected at more than 99.9% C.L.

We explore ways to quantify multipartite correlations, in quantum information and in holography. We focus on optimized correlation measures, linear combinations of entropies minimized over all possible purifications of a state that satisfy monotonicity conditions. These contain far more information about correlations than entanglement entropy alone. We present a procedure to derive such quantities and construct a menagerie of symmetric optimized correlation measures on three parties. These include tripartite generalizations of the entanglement of purification, the squashed entanglement, and the recently introduced $Q$ correlation and $R$ correlation. Some correlation measures vanish only on product states and, thus, quantify both classical and quantum correlations; others vanish on any separable state, capturing quantum correlations alone. We then use a procedure motivated by the surface-state correspondence to construct holographic duals for the correlation measures as linear combinations of bulk surfaces. The geometry of the surfaces can preserve, partially break, or fully break the symmetry of the correlation measure. The optimal purification is encoded in the locations of certain points, whose locations are fixed by constraints on the areas of combinations of surfaces. This gives a new concrete connection between information theoretic quantities evaluated on a boundary state and detailed geometric properties of its dual.

Exact analytic solutions of static, stable, nonplanar Bogomol’nyi-Prasad-Sommerfield (BPS) domain wall junctions are obtained in extended Abelian-Higgs models in ($D+1$)-dimensional spacetime. For specific choice of mass parameters, the Lagrangian is invariant under the symmetric group ${\mathcal{S}}_{D+1}$ of degree $D+1$ spontaneously broken down to ${\mathcal{S}}_D$ in vacua, admitting ${\mathcal{S}}_{D+1}/{\mathcal{S}}_D$ domain wall junctions. In $D=2$, there are three vacua and three domain walls meeting at a junction point, in which the conventional topological charges $Y$ and $Z$ exist for the BPS domain wall junctions and the BPS domain walls, respectively, as known before. In $D=3$, there are four vacua, six domain walls, four junction lines on which three domain walls meet, and one junction point on which all the six domain walls meet. We define a new topological charge $X$ for the junction point in addition to the conventional topological charges $Y$ and $Z$. In general dimensions, we find that the configuration expressed in the $D$-dimensional real space is dual to a regular $D$-simplex in the $D$-dimensional internal space and that a $d$-dimensional subsimplex of the regular $D$-simplex corresponds to a ($D-d$)-dimensional intersection. Topological charges are generalized to the level-$d$ wall charge $W_d$ for the $d$-dimensional subsimplexes.

The massless three-dimensional Gross-Neveu-Yukawa (GNY) and Nambu–Jona-Lasinio–Yukawa (NJLY) models at finite temperatures are analyzed within the mean field framework considering all coupling values. When the number of Dirac fermions is taken to be $N_f=1/4$ (GNY) and $N_f=1/2$ (NJLY) these models relate to the supersymmetric Wess-Zumino (WZ) theory with cubic superpotential and one superfield. In this case the results show that the strong-weak entropy density ratio decreases from the Stefan-Boltzmann value, in the weak limit, to $s/s_{\text{free}}=31/35$ at strong couplings. This value agrees with the one recently obtained by applying the large-$N$ approximation to the supersymmetric $O(N)$ WZ model with quartic superpotential and $N$ superfields. When $N_f=0$ one obtains $s/s_{\text{free}}=4/5$ recovering, as expected, the ratio predicted in the context of the $O(N)$ scalar model. However, contrary to the $O(N)$ WZ model the simple Yukawa models analyzed here do not behave as CFTs for all couplings since the conformal measure exactly vanishes only at the extreme weak and strong limits although the speed of sound indicates that the deviation, at intermediate couplings, appears to be rather small. By comparing the thermal masses behavior in each case one can trace this difference as being a consequence that in the GNY/NJLY case the fermionic mass vanishes for all couplings while within the $O(N)$ WZ it only vanishes at the weak and strong limits. On the other hand, the Yukawa bosonic dimensionless masses display a more universal behavior decreasing from $2\ln [(1+\sqrt{5})/2]$, at infinite coupling, to zero (at vanishing coupling).

The generation of coherent superposition of distinct physical systems and the construction of robust entangled states under decoherence are the most experimental challenges of quantum technologies. In this work, we investigate the behaviors of catlike states of a deformed harmonic oscillator under dissipative decoherence. Varying the deformation parameters, we obtain catlike states having more resistance against decoherence than catlike states of the ordinary harmonic oscillator. Furthermore, we study nonclassical properties and entanglement of different catlike states subjects to decoherence caused by a dissipative interaction with a large environment. Depending on different parameters of the deformation, we reveal that the nonclassical properties of catlike states under dissipative interaction can be more retarded and preserved in the time.

We apply the canonical quantization procedure to the Dirac field inside a spherical boundary with rotating coordinates. The rotating quantum states with two kinds of boundary conditions, namely, spectral and MIT boundary conditions, are defined. To avoid faster than light, we require the speed on the surface to be less than the speed of light. For this situation, the definition of vacuum is unique and identical with the Minkowski vacuum. Finally, we calculate the thermal expectation value of the fermion condensate in a thermal equilibrium rotating fermion field and find it depends on the boundary condition.