Observation of a J^PC = 1-+ exotic resonance in diffractive dissociation of 190 GeV/c pi- into pi- pi- pi+

The COMPASS experiment at the CERN SPS has studied the diffractive dissociation of negative pions into the pi- pi- pi+ final state using a 190 GeV/c pion beam hitting a lead target. A partial wave analysis has been performed on a sample of 420000 events taken at values of the squared 4-momentum transfer t' between 0.1 and 1 GeV^2/c^2. The well-known resonances a1(1260), a2(1320), and pi2(1670) are clearly observed. In addition, the data show a significant natural parity exchange production of a resonance with spin-exotic quantum numbers J^PC = 1-+ at 1.66 GeV/c^2 decaying to rho pi. The resonant nature of this wave is evident from the mass-dependent phase differences to the J^PC = 2-+ and 1++ waves. From a mass-dependent fit a resonance mass of 1660 +- 10+0-64 MeV/c^2 and a width of 269+-21+42-64 MeV/c^2 is deduced.Comment: 7 page, 3 figures; version 2 gives some more details, data unchanged; version 3 updated authors, text shortened, data unchange

Measurement of W^±Z production cross sections and gauge boson polarisation in pp collisions at √s=13 TeV with the ATLAS detector

This work is licensed under a Creative Commons Attribution 4.0 International License.This paper presents measurements of ± production cross sections in pp collisions at a centre-of-mass energy of 13 TeV. The data were collected in 2015 and 2016 by the ATLAS experiment at the Large Hadron Collider, and correspond to an integrated luminosity of 36.1 fb−1. The ± candidate events are reconstructed using leptonic decay modes of the gauge bosons into electrons and muons. The measured inclusive cross section in the detector fiducial region for a single leptonic decay mode is fid.±→ℓ′ℓℓ=63.7± 1.0 (stat.)± 2.3 (syst.)± 1.4 (lumi.) fb, reproduced by the next-to-next-to-leading-order Standard Model prediction of 61.5+1.4−1.3 fb. Cross sections for + and − production and their ratio are presented as well as differential cross sections for several kinematic observables. An analysis of angular distributions of leptons from decays of W and Z bosons is performed for the first time in pair-produced events in hadronic collisions, and integrated helicity fractions in the detector fiducial region are measured for the W and Z bosons separately. Of particular interest, the longitudinal helicity fraction of pair-produced vector bosons is also measured

Search for heavy charged long-lived particles in the ATLAS detector in 36.1 fb−1 of proton-proton collision data at √s=13 TeV

A search for heavy charged long-lived particles is performed using a data sample of 36.1     fb − 1 of proton-proton collisions at √ s = 13     TeV collected by the ATLAS experiment at the Large Hadron Collider. The search is based on observables related to ionization energy loss and time of flight, which are sensitive to the velocity of heavy charged particles traveling significantly slower than the speed of light. Multiple search strategies for a wide range of lifetimes, corresponding to path lengths of a few meters, are defined as model independently as possible, by referencing several representative physics cases that yield long-lived particles within supersymmetric models, such as gluinos/squarks ( R -hadrons), charginos and staus. No significant deviations from the expected Standard Model background are observed. Upper limits at 95% confidence level are provided on the production cross sections of long-lived R -hadrons as well as directly pair-produced staus and charginos. These results translate into lower limits on the masses of long-lived gluino, sbottom and stop R -hadrons, as well as staus and charginos of 2000, 1250, 1340, 430, and 1090 GeV, respectively

Protein recognition in ferredoxin-P450 electron transfer in the class I CYP199A2 system from Rhodopseudomonas palustris

CYP199A2 from Rhodopseudomonas palustris CGA009 is a heme monooxygenase that catalyzes the oxidation of para-substituted benzoic acids. CYP199A2 activity is reconstituted by a class I electron transfer chain consisting of the associated [2Fe-2S] ferredoxin palustrisredoxin (Pux) and a flavoprotein palustrisredoxin reductase (PuR). Another [2Fe-2S] ferredoxin, palustrisredoxin B (PuxB; RPA3956) has been identified in the genome. PuxB shares sequence identity and motifs with vertebrate-type ferredoxins involved in Fe-S cluster assembly but also 50% identity with Pux and it mediates electron transfer from PuR to CYP199A2, albeit with lower steady-state turnover activity: 99 nmol (nmol P450)(-1)min(-1) for 4-methoxybenzoic acid oxidation compared with 1,438 nmol (nmol P450)(-1 )min(-1) for Pux. This difference mainly arises from weak CYP199A2-PuxB binding (K (m) 34.3 vs. 0.45 microM for Pux) rather than slow electron transfer (k (cat) 19.1 vs. 37.9 s(-1) for Pux). Comparison of the 2.0-A-resolution crystal structure of the PuxB A105R mutant with other vertebrate-type, P450-associated ferredoxins revealed similar protein folds but also significant differences in some loop regions. Therefore, PuxB offers a platform for studying ferredoxin-P450 recognition in class I P450 systems. Substitution of PuxB residues at key locations with those in Pux shows that Ala42, Cys43, and Ala44 in the [2Fe-2S] cluster binding loop and Met66 are important in electron transfer from PuxB to CYP199A2, whereas Phe73 and the C-terminal Ala105 were involved in both protein binding and electron transfer.Stephen G. Bell, Feng Xu, Eachan O. D. Johnson, Ian M. Forward, Mark Bartlam, Zihe Rao, Luet-Lok Won