Software performance of the ATLAS track reconstruction for LHC run 3

Charged particle reconstruction in the presence of many simultaneous proton–proton (pp) collisions in the LHC is a challenging task for the ATLAS experiment’s reconstruction software due to the combinatorial complexity. This paper describes the major changes made to adapt the software to reconstruct high-activity collisions with an average of 50 or more simultaneous pp interactions per bunch crossing (pileup) promptly using the available computing resources. The performance of the key components of the track reconstruction chain and its dependence on pile-up are evaluated, and the improvement achieved compared to the previous software version is quantified. For events with an average of 60 pp collisions per bunch crossing, the updated track reconstruction is twice as fast as the previous version, without significant reduction in reconstruction efficiency and while reducing the rate of combinatorial fake tracks by more than a factor two

Observation of four-top-quark production in the multilepton final state with the ATLAS detector

This paper presents the observation of four-top-quark (tt¯tt¯) production in proton-proton collisions at the LHC. The analysis is performed using an integrated luminosity of 140 fb−1 at a centre-of-mass energy of 13 TeV collected using the ATLAS detector. Events containing two leptons with the same electric charge or at least three leptons (electrons or muons) are selected. Event kinematics are used to separate signal from background through a multivariate discriminant, and dedicated control regions are used to constrain the dominant backgrounds. The observed (expected) significance of the measured tt¯tt¯ signal with respect to the standard model (SM) background-only hypothesis is 6.1 (4.3) standard deviations. The tt¯tt¯ production cross section is measured to be 22.5+6.6−5.5 fb, consistent with the SM prediction of 12.0±2.4 fb within 1.8 standard deviations. Data are also used to set limits on the three-top-quark production cross section, being an irreducible background not measured previously, and to constrain the top-Higgs Yukawa coupling and effective field theory operator coefficients that affect tt¯tt¯ production

Liver Transplantation For Budd-chiari Syndrome [transplante De Fígado Na Síndrome De Budd-chiari]

A case of acute Budd-Chiari syndrome in a 21-year-old man is reported. The transplanted liver was from a patient with the same blood. No veno-venous bypass was necessary during operation. The patient presented two major complications after liver transplantation: a) stenosis of the anastomosis of the supra hepatic inferior cava vein, treated with percutaneous angioplasty; b) biliary leak, treated with sphincterotomy. The patient is assymptomatic thirty one month after transplantation.531010541060Berenhauser-Leite, G., Souza, V., Boni, I.F.S.F., Leonardi, L.S., Percutaneous angioplasty in orthotopic liver transplantation (1995) European IHPBA Congress, pp. 807-808. , Papastamatiou, L. ed. Monduzzi, BolognaLeonardi, L.S., Callejas-Neto, F., Berenhauser-Leite, G., Boin, I.F.S.F., Endoscopy sphincterotomy in patients with biliary leak after orthotoptc liver transplantation (1995) European IHPBA Congress, pp. 269-272. , Papastamatiou, L. ed. Monduzzi, BolognaLeonardi, L.S., Berenhauser-Leite, G., Boin, I.F., Santos, M.C., Udo, E.Y., Avaliação psicossocial de um grupo de doentes submetidos a transplante hepático (1994) Resumo dos Trabalhos Científicos da I Semana Brasileira do Aparelho Digestivo, p. 148. , Porto AlegreShill, M., Henderson, J.M., Tavill, A.S., The Budd-Chiari syndrome revised (1994) Gastroenterologist, 2, pp. 27-38Sanchez-Bueno, F., Parrilha, P., Ramirez, P., Robles, R., Pons, J.A., Acosta, F., Nuñez, R., Sanchez-Ortega, J.L., Transplante ortotópico de higado en el síndrome de Budd-Chiari. Presentación de un caso (1992) Rev. Esp. Enf. Digest, 81, pp. 52-56Rodes, J., Prieto, J., Rapado, A., Dotor abdominal y ascitis (1995) Gastroenterología y Hepatología, pp. 169-173. , Panéz, J. ed. Masson-Salvat, BarcelonaHalft, G., Todo, S., Tzakis, A., Gordon, R., Starzl, T.E., Liver transplantation for the Budd-Chiari Syndrome (1990) Ann. Surg., 211, pp. 43-49Berenhauser-Leite, G., Complicações da cirrose hepática (1995) Ped. Mod., 31, pp. 366-374Kane, R., Eustace, S., Diagnosis of Budd-Chiari syndrome: Comparison between sonography and MR angiography (1995) Radiology, 195, pp. 117-121Berenhauser-Leite, G., Anatomia cirúrgica do fígado (1995) Arq. Cat. Med., 24, pp. 33-37Mahmoud, A.E.A., Gakis, D., Oliffe, S., West, R., Buckels, J., Elias, E., Mesocaval shunt versus radiological intervention in the treatment of Budd-Chiari syndrome (1995) HPBSE, 9 S, p. 63Baulieux, J., De La Roche, E., Genin, G., Ducerf, C., Pignal, C., Petipas, E., Adham, M., Pouyet, M., Interest of transjugular intrahepatic porto-systemic shunt before orthotopic liver transplantation (1995) HPBSE, 9 S, p. 117Rogopoulos, A., Gavelli, A., Sakai, H., McNamara, M., Huguet, C., Transjugular intrahepatic portosystemic shunt for Budd-Chiari syndrome after failure of surgical shunting (1995) Arch. Surg., 130, pp. 227-228Jamieson, N.V., Williams, R., Calne, R.Y., Liver transplantation for Budd-Chiari syndrome, 1976-1990 (1991) Ann. Chir, 45, pp. 362-365Moreno-Gonzalez, E., Landa-Garcia, I., Calleja-Kempin, J., Gomez-Gutierrez, M., Jover-Navalon, J.M., Anas-Dtaz, J., Berenhauser-Leite, G., Comparação dos resultados do transplante hepático em duas fases de um programa (1988) Rev. Col. Bras. Cirurg., 15, p. 94Zajko, A.B., Claus, D., Clapuyt, P., Esquivel, C., Moulin, D., Starzl, T.E., Goyet, J.V.G., Otte, J.B., Obstruction to hepatic venous drainage after liver transplantation: Treatment with ballon angioplasty (1989) Radiology, 170, pp. 763-765Donovan, J., Nosurgical management of biliary tract dease after liver transplantation. Gastroenterol (1993) Clin. N. Am., 22, pp. 317-33