We present a study of the sensitivity to models of new physics of proton collisions resulting in three electroweak bosons. As a benchmark, we analyze models in which an exotic scalar field $\varphi$ is produced in association with a gauge boson ($V=\gamma$ or $Z$). The scalar then decays to a pair of bosons, giving the process $pp\to \varphi V\to V^{\prime }{V}^{\prime \prime }V$. We interpret our results in a set of effective field theories where the exotic scalar fields couple to the Standard Model through pairs of electroweak gauge bosons. We estimate the sensitivity of the LHC and HL-LHC datasets and find sensitivity to cross sections in the 10 fb–0.5 fb range, corresponding to scalar masses of 500 GeV to 2 TeV and effective operator coefficients up to 35 TeV.

We perform large scale simulations to characterize the transition in quenched QCD. It is shown by a rigorous finite size scaling that the transition is of first order. After this qualitative feature, quantitative results are obtained with unprecedented precision: We calculate the transition temperature $w_0{T}_c=0.25384(23)$—which is the first per-mill accurate result in QCD thermodynamics—and the latent heat $\mathrm{\Delta }E/T_c^4=1.025(21)(27)$, in both cases carrying out controlled continuum and infinite volume extrapolations. As it is well known, the cost of lattice simulations explodes in the vicinity of phase transitions, a phenomenon called critical slowing down for second order phase transitions and supercritical slowing down for first order phase transitions. We show that a generalization of the parallel tempering algorithm of Marinari and Parisi [Europhys. Lett. 19, 451 (1992)] originally for spin systems can efficiently overcome these difficulties even if the transition is of first order, like in the case of QCD without quarks, or with very heavy quarks. We also report on our investigations on the autocorrelation times and other details.

A set of optimized interpolating operators which are dominantly coupled to each eigenstate of two baryons on the lattice is constructed by the HAL QCD method. To test its validity, we consider heavy dibaryons ${\mathrm{\Omega }}_{3Q}{\mathrm{\Omega }}_{3Q}$ ($Q=s$, $c$) calculated by ($2+1$)-flavor lattice QCD simulations with nearly physical pion mass. The optimized two-baryon operators are shown to provide effective energies of the ground and excited states, separately stable as a function of the Euclidean time. Also they agree with the eigenenergies in a finite lattice box obtained from the leading-order HAL QCD potential $V(\mathit{r})$ within statistical errors. The overlapping factors between the optimized sink operators and the state created by the wall-type source operator indicate that $V(\mathit{r})$ can be reliably extracted, no matter whether the spacetime correlation of two baryons is dominated by the ground state or the excited state. It is suggested that the optimized set of operators is useful for variational studies of hadron-hadron interactions.

We analyze the reliability of several techniques for computing jet and hadron spectra at different collision energies. This is relevant for discovering energy loss in the upcoming oxygen-oxygen (OO) run at the LHC, for which a reference $pp$ run is currently not planned. For hadrons and jets we compute the ratio of spectra between different $pp$ collision energies in perturbative QCD, which can be used to construct a reference spectrum. Alternatively, it can be interpolated from measured spectra at nearby energies. We estimate the precision of both strategies for the spectra ratio relevant to the oxygen run, and conclude that the central values agree to 4% accuracy for hadrons and 2% accuracy for jets. Finally we propose taking the ratio of OO and $pp$ spectra at different collision energies, which cleanly separates the experimental measurement and theoretical computation.

We study the two-point functions from chiral kinetic theory which characterize the response to perturbative vector and axial gauge fields in magnetized chiral plasma. In the lowest-Landau-level approximation, the solution of chiral kinetic equations gives density waves of electric and axial charges, which contain chiral magnetic waves implied by the axial anomaly and magnetic field. We then obtain the constitutive relations for covariant currents and stress tensors that involve the density waves. By considering the difference between consistent and covariant anomalies explicitly, the correlators of consistent currents and stress tensors satisfy derivative symmetry and therefore allow an effective action for the perturbative gauge fields as the generating functional of the correlators. We also verify that the derivative symmetry of the correlators agrees with the Onsager relations.

Motivated by the recent discovery of a new tetraquark $T_{cc}^{+}$ state with two charm quarks and two light quarks by LHCb Collaboration, we calculate the spectroscopic parameters; namely, the mass and residues of beauty partners of $T_{cc}^{+}$ within QCD sum rules. The obtained results are compared with the predictions of different approaches in the literature.

The $D_{s0}(2590{)}^{+}$ resonance observed by LHCb Collaboration is a strong candidate of the $D_s(2^1{S}_0)$ state according to its spin parity and strong decay mode. However, the measured mass seems relatively lower than the previous theoretical predictions, which interests the coupled channel interpretations in the literature. In this work, we adopt an alternate approach, taking into account the screening effects in the potential model, to describe the $D_{s0}(2590{)}^{+}$ resonance. The mass spectrum and strong decays of the excited charmed-strange mesons are investigated within the modified relativized quark model and ${}^3{P}_0$ model. The calculated mass and width of the $D_{s0}(2590{)}^{+}$ are consistent with the experimental observations, which indicate that it can be reasonably interpreted as the $D_s(2^1{S}_0)$ state.

We present a chiral model describing decays of the Roper-like ${\mathrm{\Lambda }}_c(2765)$ and ${\mathrm{\Xi }}_c(2970)$ as well as those of the heavy quark spin-doublet $\{{\mathrm{\Sigma }}_c(2455),{\mathrm{\Sigma }}_c(2520)\}$ and $\{{\mathrm{\Xi }}_c^{\prime },{\mathrm{\Xi }}_c(2645)\}$, by focusing on chiral representations of diquarks inside the heavy baryons. Based on our chiral model together with the heavy quark spin symmetry, we derive a relation satisfied by axial charges of the heavy baryons that controls the magnitude of their one pion (kaon) decays. Besides, it is shown that the large decay widths of the Roper-like ${\mathrm{\Lambda }}_c(2765)$ and ${\mathrm{\Xi }}_c(2970)$, which cannot be implemented by conventional nonrelativistic quark models, are explained by reasonable values of the axial charges. In addition, we apply the chiral model to bottom baryons and predict decay widths of the undiscovered Roper-like ${\mathrm{\Xi }}_b$. We expect that our present investigation leads to elucidation of dynamical properties of the excited heavy baryons from the viewpoint of chiral symmetry.

The properties of the light vector meson states around 2.0 GeV have been poorly understood for a long time, which has become a barrier to the expansion to higher light vector meson spectrum. Recently, the BESIII collaboration released the measurements of the $e^{+}{e}^{-}\to \omega {\pi }^0$ and $e^{+}{e}^{-}\to \rho {\eta }^{\prime }$ reactions above 2.0 GeV, both of which are ideal processes to study the isovector $\rho$ meson family. In this work, through carrying out a combined analysis of the Born cross section data for the above two processes with the theoretical support on mass spectrum, and production and strong decay behaviors of the $\rho$ meson family around 2.0 GeV, we identify the enhancement structure near 2034 MeV observed in $e^{+}{e}^{-}\to \omega {\pi }^0$ to be the interference contribution from two resonances $\rho (1900)$ and $\rho (2150)$, and another enhancement structure at 2111 MeV reported in $e^{+}{e}^{-}\to \rho {\eta }^{\prime }$ to be the contributions from $\rho (2000)$ and $\rho (2150)$. This conclusion means that the $e^{+}{e}^{-}\to \omega {\pi }^0$ and $e^{+}{e}^{-}\to \rho {\eta }^{\prime }$ are the excellent golden channels to establish $\rho (1900)$ and $\rho (2000)$, especially for a $D$-wave state $\rho (2000)$, whose experimental search in the $e^{+}{e}^{-}$ collision should be quite challenging. The relevant cross section measurements with higher precision are expected in the future BESIII and Belle II experiments.

In this paper, the deconfinement and chiral restoration transitions in a strong magnetic field are realized at zero temperature in the Polyakov Nambu-Jona-Lasinio model. We provide the thermodynamic treatment to mimic the deconfinement phase transition at zero temperature together with the entangled scalar and vector interactions coupled with the Polyakov loop. The magnetic catalysis is found by a rising behavior of the critical chemical potential for the first-order deconfinement phase transition. While the magnetic catalysis on the chiral restoration could convert to inverse magnetic catalysis under the running coupling interaction ansatz. Furthermore, the stronger magnetic field makes the possible quarkyonic phase window to be enlarged under the running coupling interaction.

We demonstrate that $T$ invariance can be violated even when the Pontecorvo-Maki-Nakagawa-Sakata lepton mixing matrix is real. We obtain a sufficient condition of $T$ violation in neutrino oscillations in matter and electromagnetic field. In the two-flavor model we derive the $T$-violating spin-flavor transition probabilities. Then we prove that the transition probabilities for neutrino in a moving medium in electromagnetic field differ from those for antineutrino in matter composed of antiparticles and electromagnetic field only in the sign of the $T$-violating term.

With the expected large increase in datasets, previously not measured decays will be studied at Belle II. We derive standard model predictions for the $B\to X_u\tau \overline{\nu }$ decay rate and distributions. The region in the lepton energy spectrum where higher-dimension operators in the local operator product expansion need to be resummed into the $b$-quark light-cone distribution function is a significantly greater fraction of the phase space than for massless leptons. The finite $\tau$ mass has the novel effect of shifting and squeezing how the distribution function enters the lepton energy spectrum. We also derive new predictions for the $\tau$ polarization.

Using $9.9{\mathrm{fb}}^{-1}$ of $e^{+}{e}^{-}$ collision data collected by the BESIII detector at center-of-mass energies between 4.15 and 4.30 GeV, we search for the processes $e^{+}{e}^{-}\to \gamma X(3872)$ with $X(3872)\to {\pi }^0{\chi }_{c0}$ and $X(3872)\to \pi \pi {\chi }_{c0}$. We set upper limits (at 90% C.L.) of $\frac{\mathcal{B}(X(3872)\to {\pi }^0{\chi }_{c0})}{\mathcal{B}(X(3872)\to {\pi }^{+}{\pi }^{-}J/\psi )}<3.6$, $\frac{\mathcal{B}(X(3872)\to {\pi }^{+}{\pi }^{-}{\chi }_{c0})}{\mathcal{B}(X(3872)\to {\pi }^{+}{\pi }^{-}J/\psi )}<0.56$, and $\frac{\mathcal{B}(X(3872)\to {\pi }^0{\pi }^0{\chi }_{c0})}{\mathcal{B}(X(3872)\to {\pi }^{+}{\pi }^{-}J/\psi )}<1.7$. Combined with the BESIII measurement of $X(3872)\to {\pi }^0{\chi }_{c1}$, we also set an upper limit of $\frac{\mathcal{B}(X(3872)\to {\pi }^0{\chi }_{c0})}{\mathcal{B}(X(3872)\to {\pi }^0{\chi }_{c1})}<4.5$.

We construct models of coupled semidynamical (spin) and dynamical mirror multiplets of $\mathcal{N}=4$ supersymmetric mechanics in $d=1$ harmonic superspace. Specifically, we consider a semidynamical mirror multiplet $(\mathbf{3},\mathbf{4},\mathbf{1})$ coupled to dynamical mirror multiplets $(\mathbf{1},\mathbf{4},\mathbf{3})$ and $(\mathbf{2},\mathbf{4},\mathbf{2})$. Coupling of the multiplets $(\mathbf{3},\mathbf{4},\mathbf{1})$ and $(\mathbf{1},\mathbf{4},\mathbf{3})$ yields a mirror counterpart of the earlier constructed model implying the Nahm equations for the spin variables with the bosonic component of the multiplet $(\mathbf{1},\mathbf{4},\mathbf{3})$ as an evolution parameter. We also couple the mirror multiplet $(\mathbf{2},\mathbf{4},\mathbf{2})$ to the mirror semidynamical multiplet $(\mathbf{3},\mathbf{4},\mathbf{1})$ using chiral $\mathcal{N}=4$ superspace. The models constructed admit a generalization to the $\mathrm{SU}(2|1)$ deformation of $\mathcal{N}=4$, $d=1$ Poincaré supersymmetry.

We calculate a set of conformal correlators in the critical $O(N)$ vector model in $2<d<6$ dimensions. We focus on the correlators involving the Hubbard-Stratonovich field $s$, and its composite form $s^2$. In the process, we report a number of new calculations of diagrams involving the composite $s^2$ operator. Through the calculation of the $⟨s^2{s}^{2}s⟩$ three-point function, we shed new light on a conjectured $s\to -s$ symmetry in the $s$ sector of the critical $O(N)$ vector model in $d=3$.

We propose a string theory construction for the system of two heavy quarks and two light antiquarks. The potential of the system is a function of separation between the quarks. We define a critical separation distance below which the system can be thought of mainly as a compact tetraquark. The results show the universality of the string tension and factorization at small separations expected from heavy quark-diquark symmetry. Our estimate of the screening length is in the range of lattice QCD. We also make a comparison with the potential of the $QQq$ system. The potentials look very similar at small quark separations but at larger separations they differ. The reason for this is that the flattening of the potentials happens at two well-separated scales as follows from the two different mechanisms: string breaking by light quarks for $QQq$ and string junction annihilation for $QQ\overline{q}\overline{q}$. Moreover, a similar construction can also be applied to the $\overline{Q}\overline{Q}qq$ system.

The quantization of gravity remains one of the most important—yet extremely elusive—challenges at the heart of modern physics. Any attempt to resolve this long-standing problem seems to be doomed, as the route to any direct empirical evidence (i.e., detecting gravitons) that sheds light on the quantum aspect of gravity is far beyond the current capabilities. Recently, it was discovered that gravitationally induced entanglement, tailored in the interferometric frameworks, can be used to witness the quantum nature of gravity. Even though these schemes offer promising tools for investigating quantum gravity, many fundamental and empirical aspects of the schemes are yet to be discovered. Considering the fact that, besides quantum entanglement, the quantum uncertainty and complementarity principles are the two other foundational aspects of quantum physics, the quantum nature of gravity needs to manifest all of these features. Here, we lay out an interferometric platform for testing these nonclassical aspects of quantum mechanics in the quantum gravity setting, which connects gravity and quantum physics in a broader and deeper context. As we show in this work, all of these fundamental features of quantum gravity can be framed and thoroughly analyzed in an interferometric scheme.

Long ago, Argyres and Douglas discovered a particularly simple interacting 4D $\mathcal{N}=2$ superconformal field theory (SCFT) on the Coulomb branch of $SU(3)$ $\mathcal{N}=2$ super Yang-Mills. Further hints of the theory’s simplicity arise due to the fact that it has the smallest possible value of the $c$ central charge among unitary interacting $\mathcal{N}=2$ SCFTs. The main purpose of this paper is to uncover additional aspects of this minimal Argyres-Douglas (MAD) theory’s simplicity. In particular, we argue that: (1) the MAD theory shares an infinite set of large spin thresholds in part of its operator spectrum with the free $\mathcal{N}=2$ Maxwell theory (this data is therefore invariant under generic $\mathcal{N}=2$-preserving renormalization group flows to the IR), and (2) the MAD theory has, at every order in the natural grading, the smallest number of “Schur” operators of any unitary $\mathcal{N}=2$ theory (interacting or free). We then show that property (1) has a suitable generalization for all $(A_1,A_{2k})$ cousins of the MAD theory. In particular, the corresponding large spin thresholds encode generic renormalization group flows within this class. This construction therefore gives a different handle on these flows from the one provided by the Seiberg-Witten description. To emphasize the importance of these spin thresholds, we abstractly study theories with “enough matter” to form Higgs branches and argue that infinitely many spin thresholds are small or vanishing.

Time-delay interferometry (TDI) is a data processing technique that cancels the large laser phase fluctuations affecting the one-way Doppler measurements made by unequal-arm space-based gravitational wave interferometers. By taking finite linear combinations of properly time-shifted Doppler measurements, laser phase fluctuations can be removed at any time $t$ and gravitational wave signals can be studied at the requisite level of sensitivity. In the past, other approaches to this problem have been proposed. Recently, matrix-based approaches have been put forward; two such approaches are by Vallisneri et al. and Tinto et al. In this paper, we establish a close relationship between these approaches. In fact, we show that the matrices involved in defining the operators in the two approaches exhibit an isomorphism, and therefore, in both approaches one is dealing with matrix representations of the time-delay operators.

Searching for departures from general relativity (GR) in more than one post-Newtonian (PN) phasing coefficients, called a multiparameter test, is known to be ineffective given the sensitivity of the present generation of gravitational-wave detectors. Strong degeneracies in the parameter space make the outcome of the test uninformative. We argue that principal component analysis (PCA) can remedy this problem by constructing certain linear combinations of the original PN parameters that are better constrained by gravitational-wave observations. By analyzing binary black hole events detected during the first and second observing runs (O1 and O2) of LIGO/Virgo, we show that the two dominant principal components can capture the essence of a multiparameter test. Combining five binary black hole mergers during O1 and O2, we find that the dominant linear combination of the PN coefficients obtained from PCA, $\delta {\widehat{\varphi }}_{\mathrm{PCA}}^{(1)}$, is consistent with GR within the 0.38 standard deviation of the posterior distribution. Furthermore, using a set of simulated non-GR signals in the three-detector LIGO-Virgo network with designed sensitivities, we find that the method is capable of excluding GR with high confidence as well as recovering the injected values of the non-GR parameters with good precision.