Observation of electroweak production of two jets in association with an isolated photon and missing transverse momentum, and search for a Higgs boson decaying into invisible particles at 13 TeV with the ATLAS detector

This paper presents the measurement of the electroweak production of two jets in association with a $Z\gamma$ pair with the $Z$ boson decaying into two neutrinos. It also presents the search for invisible or partially invisible decays of a Higgs boson with a mass of 125 GeV produced through vector-boson fusion with a photon in the final state. These results use data from LHC proton-proton collisions at $\sqrt{s}$ = 13 TeV collected with the ATLAS detector corresponding to an integrated luminosity of 139 fb$^{-1}$. The event signature, shared by all benchmark processes considered for measurements and searches, is characterized by a significant amount of unbalanced transverse momentum and a photon in the final state, in addition to a pair of forward jets. For electroweak production of $Z\gamma$ in association with two jets, the background-only hypothesis is rejected with an observed (expected) significance of 5.2 (5.1) standard deviations. The measured fiducial cross-section for this process is 1.31$\pm$0.29 fb. Observed (expected) upper limit of 0.37 (0.34) at 95% confidence level is set on the branching ratio of a 125 GeV Higgs boson to invisible particles, assuming the Standard Model production cross-section. The signature is also interpreted in the context of decays of a Higgs boson to a photon and a dark photon. An observed (expected) 95% CL upper limit on the branching ratio for this decay is set at 0.018 (0.017), assuming the 125 GeV Standard Model Higgs boson production cross-section

The ATLAS inner detector trigger performance in pp collisions at 13 TeV during LHC Run 2

The design and performance of the inner detector trigger for the high level trigger of the ATLAS experiment at the Large Hadron Collider during the 2016-18 data taking period is discussed. In 2016, 2017, and 2018 the ATLAS detector recorded 35.6 fb$^{-1}$, 46.9 fb$^{-1}$, and 60.6 fb$^{-1}$ respectively of proton-proton collision data at a centre-of-mass energy of 13 TeV. In order to deal with the very high interaction multiplicities per bunch crossing expected with the 13 TeV collisions the inner detector trigger was redesigned during the long shutdown of the Large Hadron Collider from 2013 until 2015. An overview of these developments is provided and the performance of the tracking in the trigger for the muon, electron, tau and $b$-jet signatures is discussed. The high performance of the inner detector trigger with these extreme interaction multiplicities demonstrates how the inner detector tracking continues to lie at the heart of the trigger performance and is essential in enabling the ATLAS physics programme

The ATLAS inner detector trigger performance in pp collisions at 13 TeV during LHC Run 2

The design and performance of the inner detector trigger for the high level trigger of the ATLAS experiment at the Large Hadron Collider during the 2016-18 data taking period is discussed. In 2016, 2017, and 2018 the ATLAS detector recorded 35.6 fb$^{-1}$, 46.9 fb$^{-1}$, and 60.6 fb$^{-1}$ respectively of proton-proton collision data at a centre-of-mass energy of 13 TeV. In order to deal with the very high interaction multiplicities per bunch crossing expected with the 13 TeV collisions the inner detector trigger was redesigned during the long shutdown of the Large Hadron Collider from 2013 until 2015. An overview of these developments is provided and the performance of the tracking in the trigger for the muon, electron, tau and $b$-jet signatures is discussed. The high performance of the inner detector trigger with these extreme interaction multiplicities demonstrates how the inner detector tracking continues to lie at the heart of the trigger performance and is essential in enabling the ATLAS physics programme

How Frequently Does out-of Hospital Sudden Unexpected Infants Death Represent the Sudden Infant Death Syndrome?

Background. 19.6 % of all fatal cases among Russian children who died in the first year of life are registered out-of hospital, and they are usually sudden. Out-of-hospital sudden unexpected infant death (OSUID) could be confused with sudden infant death syndrome (SIDS) followed by the wide variation in the diagnostic indicators of the syndrome.The aim of the study is to reveal the pathological changes in the tissues and organs of 420 cases of OSUID (group 1) compared with 350 cases of death in the hospital (group 2), to estimate the conformity of the final diagnoses and to identify cases of OSUID, which were SIDS.Methods. From 2009 to 2016 pathoanatomical and virological study of the organs of 420 cases of OSUID (group 1) and 350 babies who died in a hospital were carried out.Results. It was established that the age of infants of the 1st group at the time of death in 71 % of cases corresponded to the age of SIDS. In terms of gestational age and body weight at birth babies of the 1st group turned out to be much more prosperous. Signs of rapid onset of death in this group: plethora of internal organs (83.3 %) and petechial hemorrhages (75.5 %) were present significantly more often than in the 2nd. In the 1st group, predominantly light acute respiratory viral infections (ARVI) with minimal pathologic signs and pneumonia were diagnosed, but pneumonia in 33.3 % not detected at autopsy. Purulent tracheobronchitis (0 and 21.4 %), bacterial pneumonia (6.3 and 26.3 %), a large area of lung damage (3.8 and 56.1 %) were detected much less frequently in the 1st group. In 38 % of the 1st group, pneumonia was the only cause of death, and in no case in the 2nd. Pathology of the cardiovascular system (55.2 and 87.7 %), central nervous system (58.6 and 90.9 %);urogenital system (34.8 and 62.9), inflammation of the membranes and brain tissue (21.9 and 70.0 %), signs of past or current intrauterine viral infection (29.5 and 64.0 %) in the 1st group was diagnosed much less frequently than in the 2nd, but congenital syphilis, HIV infection and hepatitis C — 3 times more often (12.9 and 3.7 %). The more frequent pathology of the adrenal glands in the 1st group (66.7 and 34 %) could cause inadequate responses to minimal exposure to external factors, including mild acute respiratory viral infections. The diagnosis of SIDS was made in 3 cases and in 3 more it was questionable. However, the presence of multisystemic pathology excludes the diagnosis of SIDS. The diagnosis of SIDS could be established in 30 cases in cases of slight ARVI without intoxication, shock liver or disseminated intravascular coagulation syndrome.Conclusion. The most cases of sudden death occurred in not obvious life-threatening conditions in socially disadvantaged families in the absence of adequate observation, diagnosis and treatment

A self-consistent approximation to the Kohn-Sham exchange potential.

A scheme of approximation of the Kohn-Sham exchange potential vx is proposed, making use of a partitioning of vx into the long-range Slater vS and the short-range response vresp components. A model potential vrespmod has been derived from dimensional arguments. It possesses the proper short-range behavior and the atomic-shell stepped structure characteristic for vresp. When combined with the accurate vS, vrespmod provides an excellent approximation to the exchange potential of the optimized potential model vxOPM. With the generalized-gradient approximation to vS vrespmod provides an efficient density-functional-theory approach that fits closely the form of the accurate exchange potential and yields reasonably accurate exchange and total energies as well as the energy of the highest occupied orbital. © 1995 The American Physical Society