The X-Ray Outburst of PG 1553+113: A Precession Effect of Two Jets in the Supermassive Black Hole Binary System

Blazar PG 1553+113 is thought to be a host of supermassive black hole binary system. A 2.2 yr quasi-periodicity in the γ-ray light curve was detected, possibly a result of jet precession. Motivated by the previous studies based on the γ-ray data, we analyzed the X-ray light curve and spectra observed during 2012–2020. The 2.2 yr quasi-periodicity might be consistent with the main-flare recurrence in the X-ray light curve. When a weak rebrightening in the γ-ray was observed, a corresponding relatively strong brightening in the X-ray light curve can be identified. The harder-when-brighter tendency in both X-ray main and weak flares was shown, as well as a weak softer-when-brighter behavior for the quiescent state. We explore the possibility that the variability in the X-ray band can be interpreted with two-jet precession scenario. Using the relation between jets and accretion disks, we derive the primary black hole mass ≃3.47 × 108 M ☉ and mass of the secondary one ≃1.40 × 108 M ☉, and their mass ratio ∼0.41.

Polarized Z bosons from the decay of a Higgs boson produced in association with two jets at the LHC

Investigating the polarization of weak bosons provides an important probe of the scalar and gauge sector of the Standard Model. This can be done in the Higgs decay to four leptons, whose Standard-Model leading-order amplitude enables to generate polarized observables from unpolarized ones via a fully-differential reweighting method. We study the $$\text {Z} $$ Z -boson polarization from the decay of a Higgs boson produced in association with two jets, both in the gluon-fusion and in the vector-boson fusion channel. We also address the possibility of extending the results of this work to higher orders in perturbation theory.

A Machine Learning approach to the EFT re-interpretation of the WZjj fully leptonic electroweak production

In this paper we study the use of Machine Learning techniques to set constraints on indirect signatures of physics beyond the Standard Model in Vector Boson Scattering (VBS), in the electroweak (EWK) production of self-interacting W ± Z bosons in association with two jets. The WZ fully leptonic channel has been extensively studied by the ATLAS Collaboration at the LHC and we are about to provide results using the full Run 2 data corresponding to an integrated luminosity of 139fb −1. The EWK production of the WZ in association with two jets has been already observed at 36fb −1 with an observed significance of 5.3 standard deviations. A factor of four increase in the integrated luminosity provides an opportunity to check for deviations from the Standard Model (SM) predictions, in particular for model independent, indirect searches for New Physics. Such searches can be realized in the context of an extension of the SM in terms of an Effective Field Theory (EFT) formalism, providing a way to quantify possible deviations from the Standard Model. The EFT Lagrangian besides the Standard Model terms comprises contributions from higher dimension operators, their effect being determined by the strength of their corresponding parameters (Wilson coefficients scaled to the appropriate power of Λ, indicating the scale of the appearance of New Physics). In this paper an attempt is made to search for New Physics effects in the WZjj production, using state-of-the-art machine learning models where diverse network architectures are effectively combined into ensembles trained on the outcomes of base learners maximizing performance. The base learners are trained to identify pure WZjj signal events originating from the effect of EFT operators, from WZjj background events originating from strong (QCD) or EWK WZjj processes. We investigate the utilization of the ensemble model response in estimating the sensitivity of WZjj events in some of the dimension-8 EFT operators and compare the results to sensitive kinematic variables traditionally used to constrain the EFT operator effects.

Studies on dimension-eight genuine Quartic Boson Coupling operators

Vector Boson Scattering (VBS) processes provide a great source of information on the structure of the Quartic Gauge Boson Couplings (QGCs). The Standard Model allows self interactions of the charged vector gauge bosons, although vertices with neutral-only bosons are forbidden. In this paper we use Monte Carlo samples containing VBS events with two Z-bosons in association with two jets, and we present preliminary studies for the setting of constraints on anomalous quartic couplings. In these studies we investigate typical kinematic variables and we classify them according to their sensitivity to aQGC effects. Finally, we evaluate the cross-section enhancement by each one of the dimension-eight QGC operators in the ZZjj channel.

Successful mitral valve-in-ring repair of mitral annuloplasty ring dehiscence causing severe mitral regurgitation—a case report

Background Annuloplasty failure caused by ring dehiscence can lead to trans-ring and para-ring mitral regurgitation. Transcatheter treatments are available for patients at prohibitive risk of surgery. In patients unsuitable for edge-to-edge repair, valve-in-ring transcatheter mitral valve implantation has been described to treat trans-ring or para-ring jets but not both concurrently. Case summary A 78-year-old male presented with severe mitral regurgitation due to dehiscence of a 34 mm Edwards Physio II mitral annuloplasty ring. Transesophageal echocardiography showed two jets of regurgitation; trans-ring and para- ring. Repair was successfully undertaken with a valve-in-ring procedure (29 mm S3 Edwards Lifesciences). Discussion Patients with failure of mitral valve annuloplasty with trans-ring and para-ring regurgitation can be safely and effectively treated by valve-in-ring transcatheter mitral valve implantation.

Time-delayed electrons from neutral currents at the LHC

We investigate long-lived particles (LLPs) produced in pair from neutral currents and decaying into a displaced electron plus two jets at the LHC, utilizing the proposed minimum ionizing particle timing detector at CMS. We study two benchmark models: the R-parity-violating supersymmetry with the lightest neutralinos being the lightest supersymmetric particle and two different U(1) extensions of the standard model with heavy neutral leptons (HNLs). The light neutralinos are produced from the standard model Z-boson decays via small Higgsino components, and the HNLs arise from decays of a heavy gauge boson, Z′. By simulating the signal processes at the HL-LHC with the center-of-mass energy $$ \sqrt{s} $$ s = 14 TeV and integrated luminosity of 3 ab−1, our analyses indicate that the search strategy based on a timing trigger and the final state kinematics has the potential to probe the parameter space that is complementary to other traditional LLP search strategies such as those based on the displaced vertex.

Numerical study on mean flow field of turbulent dual offset jet

A numerical investigation on the mean flow and turbulence characteristics of dual offset jet for various separation distances between the two jets with a fixed offset height of the lower jet from the bottom wall is reported in this study. The numerical simulations have been performed by solving the Reynolds-averaged Navier-Stokes equations (RANS) with two-equation standard [Formula: see text] turbulence model. The Reynolds number based on the jet width and the inlet turbulence intensity are considered as 15,000 and 5%, respectively. The computational results for the mean flow reveal that after issuing from the nozzles, the adjacent shear layers of the offset jets meet together at the merging point and then the merged jets reattaches on the bottom wall at the reattachment point before they combine together at the combined point forming a single jet flow. In the far downstream, the flow field behaves like a classical single wall jet flow. The self-similarity of mean flow field is achieved at far down stream of combined point. An increase in separation distance between the two jets [Formula: see text] results in a decrease in magnitude of the streamwise maximum velocity of the combined jet but with same rate of decay. The converging region of the jets has depicted considerable growth of turbulence as the jet centrelines bend towards the merging point. According to the mean flow results, the distances of the reattachment point and the combined point from the nozzle exit gradually increase with the progressive increase in separation distance between the two jets within the range d/ w = 3–8.

Reynolds Number Effect on the Flow Demeanorin a Vertical Circular Free Turbulent Jet with Cross Flow

This paper deals with studying numerically two circular turbulent jets impinging on a flat surface with a low velocity cross flow by using ANSYS CFX 16.2, with the aim of proving the effect ofReynolds number on the flow demeanor in a vertical circular free turbulent jet with cross flow. Five turbulence models of the RANS (Reynolds Averaged Navier–Stokes) approach were tested and the k -ω SST model was chosen to validate CFD results with the experimental data. Average velocity profiles, velocity and turbulent kinetic energy contours and streamlines are presented for four case configurations. In the first three cases, the following parameters have been varied: Reynolds number at the level of the two jets ( ), wind velocity at the level of the cross-flow ( ), and the distance between the two jets (S = 45mm, 90mm and 135mm). In the last case, a new configuration of the phenomenon not yet studied so far was treated, where horizontal cross-flows were introduced from both sides in order to simulate gusts of wind disrupting a VSTOL aircraft which tries to operate close to the ground. This case was carried out for Reynolds number based on the crossflow of 4 104, 10 104 and 20 104 .The numerical results obtained show that the deflection of the jets is minimal when the Reynolds number at the level of the jets is greater than that of the cross-flow. The increase of Reynolds number at the level of the cross-flow reveals a significant deviation of the two jets with an intensity which always remains less for the second jet. As for the space parameter between the two jets, it turns out that the fact of further spacing the two jets makes the first jet even more vulnerable and leads to a greater deflection. Finally, the simulation of the wind gusts from the front and the back caused a zone of turbulence which resulted from a form of "interlacing" of the two jets under the effect of the transverse current imposed by the two sides.