We report the first observation of the decays $B^0\to p\overline{\mathrm{\Lambda }}{D}^{(*)-}$. The data sample of $711{\mathrm{fb}}^{-1}$ used in this analysis corresponds to $772\times {10}^6$ $B\overline{B}$ pairs, collected at the $\mathrm{\Upsilon }(4S)$ resonance by the Belle detector at the KEKB asymmetric-energy $e^{+}{e}^{-}$ collider. We observe $19.8\sigma$ and $10.8\sigma$ excesses of events for the two decay modes and measure the branching fractions of $B^0\to p\overline{\mathrm{\Lambda }}{D}^{-}$ and $B^0\to p\overline{\mathrm{\Lambda }}{D}^{*-}$ to be $(25.1\pm 2.6\pm 3.5)\times 10^{-6}$ and $(33.6\pm 6.3\pm 4.4)\times 10^{-6}$, respectively, where the first uncertainties are statistical and the second are systematic. These results are not compatible with the predictions based on the generalized factorization approach. In addition, a threshold enhancement in the dibaryon ($p\overline{\mathrm{\Lambda }}$) system is observed, consistent with that observed in similar $B$ decays.

A neutral structure in the $D{\overline{D}}^{*}$ system around the $D{\overline{D}}^{*}$ mass threshold is observed with a statistical significance greater than $10\sigma$ in the processes $e^{+}{e}^{-}\to D^{+}{D}^{*-}{\pi }^0+\mathrm{c}\mathrm{.}\mathrm{c}\mathrm{.}$ and $e^{+}{e}^{-}\to D^0{\overline{D}}^{*0}{\pi }^0+\mathrm{c}\mathrm{.}\mathrm{c}\mathrm{.}$ at $\sqrt{s}=4.226$ and 4.257 GeV in the BESIII experiment. The structure is denoted as $Z_c(3885{)}^0$. Assuming the presence of a resonance, its pole mass and width are determined to be $[3885.7_{-5.7}^{+4.3}(\mathrm{stat})\pm 8.4(\mathrm{syst})]\mathrm{MeV}/c^2$ and $[35_{-12}^{+11}(\mathrm{stat})\pm 15(\mathrm{syst})]\mathrm{MeV}$, respectively. The Born cross sections are measured to be $\sigma [e^{+}{e}^{-}\to Z_c(3885{)}^0{\pi }^0,Z_c(3885{)}^0\to D{\overline{D}}^{*}]=[77\pm 13(\mathrm{stat})\pm 17(\mathrm{syst})]\mathrm{pb}$ at 4.226 GeV and $[47\pm 9(\mathrm{stat})\pm 10(\mathrm{syst})]\mathrm{pb}$ at 4.257 GeV. The ratio of decay rates $\mathcal{B}[Z_c(3885{)}^0\to D^{+}{D}^{*-}+\mathrm{c}.\mathrm{c}.]/\mathcal{B}[Z_c(3885{)}^0\to D^0{\overline{D}}^{*0}+\mathrm{c}.\mathrm{c}.]$ is determined to be $0.96\pm 0.18(\mathrm{stat})\pm 0.12(\mathrm{syst})$, consistent with no isospin violation in the process, $Z_c(3885{)}^0\to D{\overline{D}}^{*}$.

Collisions between prolate uranium nuclei are used to study how particle production and azimuthal anisotropies depend on initial geometry in heavy-ion collisions. We report the two- and four-particle cumulants, $v_2\{2\}$ and $v_2\{4\}$, for charged hadrons from $\mathrm{U}+\mathrm{U}$ collisions at $\sqrt{s_{\mathrm{NN}}}=193\mathrm{GeV}$ and $\mathrm{Au}+\mathrm{Au}$ collisions at $\sqrt{s_{\mathrm{NN}}}=200\mathrm{GeV}$. Nearly fully overlapping collisions are selected based on the energy deposited by spectators in zero degree calorimeters (ZDCs). Within this sample, the observed dependence of $v_2\{2\}$ on multiplicity demonstrates that ZDC information combined with multiplicity can preferentially select different overlap configurations in $\mathrm{U}+\mathrm{U}$ collisions. We also show that $v_2$ vs multiplicity can be better described by models, such as gluon saturation or quark participant models, that eliminate the dependence of the multiplicity on the number of binary nucleon-nucleon collisions.

We report on the rotational-state-dependent, transverse acceleration of ${\mathrm{CS}}_2$ molecules affected by pulsed optical standing waves. The steep gradient of the standing wave potential imparts far stronger dipole forces on the molecules than propagating pulses do. Moreover, large changes in the transverse velocities (i.e., up to $80\mathrm{m}/\mathrm{s}$) obtained with the standing waves are well reproduced in numerical simulations using the effective polarizability that depends on the molecular rotational states. Our analysis based on the rotational-state-dependent effective polarizability can therefore serve as a basis for developing a new technique of state selection for both polar and nonpolar molecules.

Recent findings on the similarity between electron and positronium scattering at the same velocity [Brawley et al., Science 330, 789 (2010)] have guided us towards the realization of a detectable flux of positronium atoms at beam energies five times lower than previously obtained, enabling total cross sections to be measured in the energy range $\sim (1–7)\mathrm{eV}$ for the first time. In collision with Ar and Xe, the total cross sections of positronium are found to be smallest at the lowest energy probed, approaching those of the Ramsauer-Townsend minima for electron projectiles. Additional structure has been observed in the case of positronium scattering at incident energies around 5 eV.

An optically thick cold atomic cloud emits a coherent flash of light in the forward direction when the phase of an incident probe field is abruptly changed. Because of cooperativity, the duration of this phenomena can be much shorter than the excited lifetime of a single atom. Repeating periodically the abrupt phase jump, we generate a train of pulses with short repetition time, high intensity contrast, and high efficiency. In this regime, the emission is fully governed by cooperativity even if the cloud is dilute.

We introduce a method for calculating the probability with which a low-energy electron hitting the wall of a bounded plasma gets stuck in it and apply the method to a dielectric wall with positive electron affinity smaller than the band gap using MgO as an example. In accordance with electron beam scattering data we obtain energy-dependent sticking probabilities significantly less than unity and question thereby for electrons the perfect absorber assumption used in plasma modeling.

A chiral $d$-wave superfluid is a preliminary example of interacting topological matter. However, unlike $s$-wave superfluids prevalent in nature, its existence requires a strong $d$-wave interaction, a criterion that is difficult to access in ordinary systems. There is no experimental observation of such unconventional superfluid at the moment. Here, we present a new principle for creating a two-dimensional (2D) chiral $d$-wave superfluid using periodically driven lattices. Because of an imprinted 2D pseudospin-orbit coupling, where the sublattice index serves as the pseudospin, the $s$-wave interaction between two hyperfine spin states naturally creates a chiral $d$-wave superfluid. This scheme can be directly implemented in current experiments.

We measure the magnetotransport properties of the three-dimensional Dirac semimetal ${\mathrm{Cd}}_3{\mathrm{As}}_2$ single crystal under magnetic fields up to 36 T. Shubnikov–de Haas (SdH) oscillations are clearly resolved and the $n=1$ Landau level is reached. A detailed analysis on the intercept of the Landau index plot reveals a significant dependence of the SdH phase factor on the orientation of the applied magnetic field. When the magnetic field is applied in the [001] direction, i.e., along the fourfold screw axis of the tetragonal crystal structure, a nontrivial $\pi$ Berry phase, as predicted for the Dirac fermions, is observed. However, in a magnetic field tilted away from the [001] direction, the $\pi$ Berry phase is evidently reduced, and a considerable enhancement of the effective mass is also revealed. Our observations demonstrate that the Dirac dispersion in ${\mathrm{Cd}}_3{\mathrm{As}}_2$ is effectively modified in a tilted magnetic field, whereas the preserved $\pi$ Berry phase in a magnetic field along the [001] direction can be related to the realization of the Weyl fermions. The sudden change of the SdH phase also indicates a possible topological phase transition induced by the symmetry-breaking effect.

Barium bismuth oxide (${\mathrm{BaBiO}}_3$) is the end member of two families of high-$T_c$ superconductors, i.e., ${\mathrm{BaPb}}_{1-x}{\mathrm{Bi}}_x{\mathrm{O}}_3$ and ${\mathrm{Ba}}_{1-x}{\mathrm{K}}_x{\mathrm{BiO}}_3$. The undoped parent compound is an insulator, exhibiting a charge density wave that is strongly linked to a static breathing distortion in the oxygen sublattice of the perovskite structure. We report a comprehensive spectroscopic and x-ray diffraction study of ${\mathrm{BaBiO}}_3$ thin films, showing that the minimum film thickness required to stabilize the breathing distortion and charge density wave is $\approx 11$ unit cells, and that both phenomena are suppressed in thinner films. Our results constitute the first experimental observation of charge density wave suppression in bismuthate compounds without intentionally introducing dopants.

We study a twisted Hubbard tube modeling the $[\mathrm{CrAs}{]}_{\infty }$ structure of quasi-one-dimensional superconductors $A_2{\mathrm{Cr}}_3{\mathrm{As}}_3$ ($A=\mathrm{K}$, Rb, Cs). The molecular-orbital bands emerging from the quasi-degenerate atomic orbitals are exactly solved. An effective Hamiltonian is derived for a region where three partially filled bands intersect the Fermi energy. The deduced local interactions among these active bands show a significant reduction compared to the original atomic interactions. The resulting three-channel Luttinger liquid shows various interaction-induced instabilities including two kinds of spin-triplet superconducting instabilities due to gapless spin excitations, with one of them being superseded by the spin-density-wave phase in the intermediate Hund’s coupling regime. The implications of these results for the alkali chromium arsenides are discussed.

We develop a microscopic and gauge-invariant theory for collective modes resulting from the phase of the superconducting order parameter in noncentrosymmetric superconductors. Considering various crystal symmetries, we derive the corresponding gauge mode ${\omega }_G(\mathbf{q})$ and find, in particular, new Leggett modes ${\omega }_L(\mathbf{q})$ with characteristic properties that are unique to noncentrosymmetric superconductors. We calculate their mass and dispersion that reflect the underlying spin-orbit coupling and thus the balance between triplet and singlet superconductivity occurring simultaneously. Finally, we demonstrate the role of the Anderson-Higgs mechanism: while the long-range Coulomb interaction shifts ${\omega }_G(\mathbf{q})$ to the condensate plasma mode ${\omega }_P(\mathbf{q})$, it leaves the mass ${\mathrm{\Lambda }}_0$ of the new Leggett mode unaffected and only slightly modifies its dispersion.

The glass transition of colloidal dispersions interacting with both a short-ranged attraction and long-ranged repulsion is studied using highly purified lysozyme solutions. Newtonian liquid behavior is observed at all conditions while measurements of the dynamics in the short-time limit show features typical of glassy colloidal systems at high protein concentrations. This interesting behavior is due to the competition of the attraction and repulsion that produces a heterogeneous microstructure only at intermediate range length scales. The results demonstrate that theories for the macroscopic properties of systems with competing interactions need to include intermediate range order.

Using simulation and numerical self-consistent field theory of an unentangled diblock copolymer melt, we study the interplay between relaxation of molecular conformations from a highly stretched, nonequilibrium state and structure formation of the local, conserved density during self-assembly from a disordered state. We observe that the planar elongation of molecular conformations in the initial, disordered state results in an alignment of lamella normals perpendicular to the stretch direction during the subsequent self-assembly. Although thermodynamically the parallel orientation is favored, the alignment of the lamella normal perpendicular to the stretch direction is characterized by the larger growth rate of composition fluctuations during the spinodal ordering process.

Fractional Brownian motion is a non-Markovian Gaussian process $X_t$, indexed by the Hurst exponent $H$. It generalizes standard Brownian motion (corresponding to $H=1/2$). We study the probability distribution of the maximum $m$ of the process and the time $t_{\max }$ at which the maximum is reached. They are encoded in a path integral, which we evaluate perturbatively around a Brownian, setting $H=1/2+ϵ$. This allows us to derive analytic results beyond the scaling exponents. Extensive numerical simulations for different values of $H$ test these analytical predictions and show excellent agreement, even for large $ϵ$.

Gravity theories beyond general relativity typically predict dipolar gravitational emission by compact-star binaries. This emission is sourced by “sensitivity” parameters depending on the stellar compactness. We introduce a general formalism to calculate these parameters, and show that in shift-symmetric Horndeski theories stellar sensitivities and dipolar radiation vanish, provided that the binary’s dynamics is perturbative (i.e., the post-Newtonian formalism is applicable) and cosmological-expansion effects can be neglected. This allows one to reproduce the binary-pulsar-observed orbital decay.

We present a renormalizable theory that includes a $W^{\prime }$ boson of mass in the 1.8–2 TeV range, which may explain the excess events reported by the ATLAS Collaboration in a $WZ$ final state, and by the CMS Collaboration in $e^{+}{e}^{-}jj$, $W{h}^0$, and $jj$ final states. The $W^{\prime }$ boson couples to right-handed quarks and leptons, including Dirac neutrinos with TeV-scale masses. This theory predicts a $Z^{\prime }$ boson of mass in the 3.4–4.5 TeV range. The cross section times branching fractions for the narrow $Z^{\prime }$ dijet and dilepton peaks at the 13 TeV LHC are 10 and 0.6 fb, respectively, for $M_{Z^{\prime }}=3.4\mathrm{TeV}$, and an order of magnitude smaller for $M_{Z^{\prime }}=4.5\mathrm{TeV}$.

We present the calculations on a novel reorientation effect of deuteron attributed to isovector interaction in the nuclear field of heavy target nuclei. The correlation angle determined by the relative momentum vector of the proton and the neutron originating from the breakup deuteron, which is experimentally detectable, exhibits significant dependence on the isovector nuclear potential but is robust against the variation of the isoscaler sector. In terms of sensitivity and cleanness, the breakup reactions induced by the polarized deuteron beam at about $100\mathrm{MeV}/\mathrm{u}$ provide a more stringent constraint to the symmetry energy at subsaturation densities.