Abstract: To study the properties of the N*(1535) and N*(1650), we calculate the mass distributions of MB in the Lambda(c) -> (K) over bar (MB)-M-0 decay, with MB = pi N(I = 1/2), eta p, and K Sigma(I = 1/2). We do this by calculating the tree-level and loop contributions, mixing pseudoscalar-baryon and vector-baryon channels using the local hidden gauge formalism. The loop contributions for each channel are calculated using the chiral unitary approach. We observe that for the eta N mass distribution only the N* (1535) is seen, with the N* (1650) contributing to the width of the curve, but for the pi N mass distribution both resonances are clearly visible. In the case of MB = K Sigma, we found that the strength of the K E mass distribution is smaller than that of the mass distributions of the pi N and eta p in the Lambda(+)(c)-> (K) over bar (0)pi N and Lambda(+)(c) -> (K) over bar (0)eta p processes, in spite of this channel having a large coupling to the N* (1650). This is because the K Sigma pair production is suppressed in the primary production from the Lambda(c) decay.

Abstract: The occurrence of octupolar shapes in the Ba isotopic chain was recently established experimentally up to N = 90. To further extend the systematics, the evolution of shapes in the most neutron-rich members of the Z = 56 isotopic chain accessible at present, Ba-148,Ba-150, has been studied via beta decay at the ISOLDE Decay Station. This paper reports on the first measurement of the positive-and negative-parity low-spin excited states of 150Ba and presents an extension of the beta-decay scheme of Cs-148. Employing the fast timing technique, half-lives for the 2(1)(+) level in both nuclei have been determined, resulting in T-1/2 = 1.51(1) ns for Ba-148 and T-1/2 = 3.4(2) ns for Ba-150. The systematics of low-spin states, together with the experimental determination of the B(E2 : 2(+) -> 0(+)) transition probabilities, indicate an increasing collectivity in Ba148-150, towards prolate deformed shapes. The experimental data are compared to symmetry conserving configuration mixing (SCCM) calculations, confirming an evolution of increasingly quadrupole deformed shapes with a definite octupolar character.

Abstract: ACoulomb-excitation experiment to study electromagnetic properties of Ca-42 was performed using a 170-MeV calcium beam from the TANDEM XPU facility at INFN Laboratori Nazionali di Legnaro. gamma rays from excited states in Ca-42 were measured with the AGATA spectrometer. The magnitudes and relative signs of ten E2 matrix elements coupling six low-lying states in Ca-42, including the diagonal E2 matrix elements of 2(1)(+) and 2(2)(+) states, were determined using the least-squares code GOSIA. The obtained set of reduced E2 matrix elements was analyzed using the quadrupole sum rule method and yielded overall quadrupole deformation for 0(1),(+)(2) and 2(1,2)(+) states, as well as triaxiality for 0(1,2)(+) states, establishing the coexistence of a weakly deformed ground-state band and highly deformed slightly triaxial sideband in Ca-42. The experimental results were compared with the state-of-the-art large-scale shell-model and beyond-mean-field calculations, which reproduce well the general picture of shape coexistence in Ca-42.

Abstract: A detailed study of multiparticle azimuthal correlations is presented using pp data at root s = 5.02 and 13 TeV, and p+Pb data at root s(NN) = 5.02 TeV, recorded with the ATLAS detector at the CERN Large Hadron Collider. The azimuthal correlations are probed using four-particle cumulants c(n){4} and flow coefficients v(n){4} = (-c(n){4})(1/4) for n = 2 and 3, with the goal of extracting long-range multiparticle azimuthal correlation signals and suppressing the short-range correlations. The values of c(n){4} are obtained as a function of the average number of charged particles per event, < N-ch >, using the recently proposed two-subevent and three-subevent cumulant methods, and compared with results obtained with the standard cumulant method. The standard method is found to be strongly biased by short-range correlations, which originate mostly from jetswith a positive contribution to c(n){4}. The threesubevent method, on the other hand, is found to be least sensitive to short-range correlations. The three-subevent method gives a negative c(2){4}, and therefore a well-defined v(2){4}, nearly independent of < N-ch >, which implies that the long-range multiparticle azimuthal correlations persist to events with low multiplicity. Furthermore, v(2){4} is found to be smaller than the v(2){2} measured using the two-particle correlation method, as expected for long-range collective behavior. Finally, the measured values of v(2){4} and v(2){2} are used to estimate the number of sources relevant for the initial eccentricity in the collision geometry. The results based on the subevent cumulant technique provide direct evidence, in small collision systems, for a long-range collectivity involving many particles distributed across a broad rapidity interval.

Abstract: We introduce an iterative method to univocally determine the adiabatic expansion of the modes of Dirac fields in spatially homogeneous external backgrounds. We overcome the ambiguities found in previous studies and use this new procedure to improve the adiabatic regularization/renormalization scheme. We provide details on the application of the method for Dirac fields living in a four-dimensional Friedmann-Lemaitre-Robertson-Walker spacetime with a Yukawa coupling to an external scalar field. We check the consistency of our proposal by working out the conformal anomaly. We also analyze a two-dimensional Dirac field in Minkowski space coupled to a homogeneous electric field and reproduce the known results on the axial anomaly. The adiabatic expansion of the modes given here can be used to properly characterize the allowed physical states of the Dirac fields in the above external backgrounds.