Evidence for the h_b(1P) meson in the decay Upsilon(3S) --> pi0 h_b(1P)

Using a sample of 122 million Upsilon(3S) events recorded with the BaBar detector at the PEP-II asymmetric-energy e+e- collider at SLAC, we search for the $h_b(1P)$ spin-singlet partner of the P-wave chi_{bJ}(1P) states in the sequential decay Upsilon(3S) --> pi0 h_b(1P), h_b(1P) --> gamma eta_b(1S). We observe an excess of events above background in the distribution of the recoil mass against the pi0 at mass 9902 +/- 4(stat.) +/- 2(syst.) MeV/c^2. The width of the observed signal is consistent with experimental resolution, and its significance is 3.1sigma, including systematic uncertainties. We obtain the value (4.3 +/- 1.1(stat.) +/- 0.9(syst.)) x 10^{-4} for the product branching fraction BF(Upsilon(3S)-->pi0 h_b) x BF(h_b-->gamma eta_b).Comment: 8 pages, 4 postscript figures, submitted to Phys. Rev. D (Rapid Communications

Measurement of the Top Pair Production Cross Section in the Dilepton Decay Channel in ppbar Collisions at sqrt s = 1.96 TeV

Submitted to Phys. Rev. DA measurement of the \ttbar production cross section in \ppbar collisions at $\sqrt{{\rm s}}$ = 1.96 TeV using events with two leptons, missing transverse energy, and jets is reported. The data were collected with the CDF II Detector. The result in a data sample corresponding to an integrated luminosity 2.8 fb$^{-1}$ is: \sigma_{\ttbar} = 6.27 $\pm$ 0.73(stat) $\pm$ 0.63(syst) $\pm$ 0.39(lum) pb. for an assumed top mass of 175 GeV/$c^{2}$.A measurement of the tt̅ production cross section in pp̅ collisions at √s=1.96  TeV using events with two leptons, missing transverse energy, and jets is reported. The data were collected with the CDF II detector. The result in a data sample corresponding to an integrated luminosity 2.8  fb-1 is σtt̅ =6.27±0.73(stat)±0.63(syst)±0.39(lum)  pb. for an assumed top mass of 175  GeV/c2.Peer reviewe

Measurements of photo-nuclear jet production in Pb plus Pb collisions with ATLAS

Ultra-peripheral heavy ion collisions provide a unique opportunity to study the parton distributions in the colliding nuclei via the measurement of photo-nuclear jet production. An analysis of jet production in ultra-peripheral Pb+Pb collisions at √sNN = 5.02 TeV performed using data collected with the ATLAS detector in 2015 is described. The data set corresponds to a total Pb+Pb integrated luminosity of 0.38 nb−1. The ultra-peripheral collisions are selected using a combination of forward neutron and rapidity gap requirements. The cross-sections, not unfolded for detector response, are compared to results from Pythia Monte Carlo simulations re-weighted to match a photon spectrum obtained from the STARlight model. Qualitative agreement between data and these simulations is observed over a broad kinematic range suggesting that using these collisions to measure nuclear parton distributions is experimentally realisable

Heavy Ion Results from ATLAS

These proceedings provide an overview of the new results obtained with the ATLAS detector at the LHC, which were presented in the Quark Matter 2017 conference. These results were covered by twelve parallel talks, one flash talk and eleven posters. These proceedings group these results into five areas: initial state, jet quenching, quarkonium production, longitudinal flow dynamics, and collectivity in small systems

Sinapine, but not sinapic acid, counteracts mitochondrial oxidative stress in cardiomyocytes

International audienceIntroduction: When confronted to stress or pathological conditions, the mitochondria overproduce reactive species that participate in the cellular dysfunction. These organelles are however difficult to target with antioxidants. A feature of mitochondria that can be used for this is the negatively charged compartments they form. Most of mitochondrion-targeting antioxidants are therefore cationic synthetic molecules. Our hypothesis is that such mitochondriotropic traits might also exists in natural molecules.Aim: We tested here whether sinapine, a natural phenolic antioxidant-bearing a permanent positive charge, can target mitochondria to modulate mitochondrial oxidative stress.Methods: Experiments were performed in-vitro, in-cellulo, ex-vivo, and in-vivo, using cardiac tissue. The sinapic acid -lacking the positively-charged-choline-moiety present in sinapine-was used as a control. Sinapine entry into mitochondria was investigated in-vivo and in cardiomyocytes. We used fluorescent probes to detect cytosolic (H2DCFDA) and mitochondrial (DHR123) oxidative stress on cardiomyocytes induced with either hydrogen peroxide (H2O2) or antimycin A, respectively. Finally, ROS production was measured with DHE 10 min after ischemia-reperfusion (IR) on isolated heart, treated or not with sinapine, sinapic acid or with a known synthetic mitochondrion-targeted antioxidant (mitoTempo).Results: We detected the presence of sinapine within mitochondria in-vitro, after incubation of isolated cardiomyocytes, and in-vivo, after oral treatment. The presence of sinapic acid was not detected in the mitochondria. Both the sinapine and the sinapic acid limited cytosolic oxidative stress in response to H2O2. Only sinapine was able to blunt oxidative stress resulting from antimycin A-induced mtROS. Both mitoTempo and sinapine improved cardiac functional recovery following IR. This was associated with lower ROS production within the cardiac tissue.Conclusion: Sinapine, a natural cationic hydrophilic phenol, commonly and substantially found in rapeseed species, effectively (i) enters within the mitochondria, (ii) selectively decreases the level of mitochondrial oxidative stress and, (iii) efficiently limits ROS production during cardiac ischemia-reperfusion