Bulletin of the American Physical Society
APS April Meeting 2017
Volume 62, Number 1
Saturday–Tuesday, January 28–31, 2017; Washington, DC
Session M12: Heavy Flavor Hadrons |
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Sponsoring Units: DNP GHP Chair: Greg Kalicy, Catholic University of America Room: Roosevelt 4 |
Sunday, January 29, 2017 3:30PM - 3:42PM |
M12.00001: Masses of Open-Flavour Heavy-Light Hybrids from QCD Sum Rules Jason Ho, Derek Harnett, Tom Steele Our current understanding of the strong interaction (QCD) permits the construction of colour singlet states with novel structures that do not fit within the traditional quark model, including hybrid mesons. To date, though other exotic structures such as pentaquark and tetraquark states have been confirmed, no unambiguous hybrid meson signals have been observed. However, with data collection at the GlueX experiment ongoing and with the construction of the PANDA experiment at FAIR, the opportunity to observe hybrid states has never been better. As theoretical calculations are a necessary piece for the identification of any observed experimental resonance, we present our mass predictions of heavy-light open-flavour hybrid mesons using QCD Laplace sum-rules for all scalar and vector $J^{P}$ channels, and including non-perturbative condensate contributions up to six-dimensions. [Preview Abstract] |
Sunday, January 29, 2017 3:42PM - 3:54PM |
M12.00002: ABSTRACT WITHDRAWN |
Sunday, January 29, 2017 3:54PM - 4:06PM |
M12.00003: Exclusive $\eta$ photoproduction and $\Sigma$ beam asymmetries at GlueX William McGinley The goal of the GlueX experiment is to study the gluonic degrees of freedom in QCD by mapping the light meson spectrum with an emphasis on hybrid exotic states. This will be done using a tagged, linearly-polarized 9 GeV photon beam incident on a hydrogen target. Early measurements of exclusive $\eta$ photoproduction will provide insight into the reaction mechanism. The GlueX experiment is making the first $\Sigma$ beam asymmetry measurement for the $\eta$ in this energy range and is expected to further constrain Regge theory models for photoproduced pseudoscalar mesons. This talk will present preliminary results for the photon beam $\Sigma$ asymmetry for multiple decay modes of the exclusive reaction $\gamma$$p$ $\rightarrow$ $\eta$$p$ using data from a recent commissioning run. [Preview Abstract] |
Sunday, January 29, 2017 4:06PM - 4:18PM |
M12.00004: Photoproduction of $\eta'$ mesons with the GlueX experiment Mahmoud Kamel The GlueX experiment at Jefferson Lab studies the light meson spectrum and searches for hybrid and exotic mesons. In this experiment, a 9 GeV tagged, linearly polarized photon beam interacts with a liquid hydrogen target at the center of the GlueX detector. First results of the photo-production of $\eta'$ mesons at beam energies ranging from 3.5 to 11 GeV will be presented. The $\eta'$ have been identified through the decay channel $\eta'\rightarrow \pi^+ \pi^- \gamma$ , which has a large branching ratio of 29\%. No data exist for beam energies above 6 GeV for this reaction. [Preview Abstract] |
Sunday, January 29, 2017 4:18PM - 4:30PM |
M12.00005: Exclusive K+K- production by double pomeron exchange at the Fermilab Bevatron Michael Albrow We present data from proton-antiproton collisions at $\sqrt{s}$ = 1.96 TeV collected by the CDF experiment, in which a K+K- pair is reconstructed in the central region $|\eta| <$ 1.0, and no other particles are detected in the range -5.9 $< \eta <$ +5.9. Hadron collisions with such large rapidity gaps are described by double pomeron exchange where the central state has Q = B = S = 0, isospin I = 0, even spin J, positive parity P and positive charge parity C.It is therefore a quantum number filter, of particular interest for states with high gluon content, such as hybrids and glueballs. [Preview Abstract] |
Sunday, January 29, 2017 4:30PM - 4:42PM |
M12.00006: b quark production at a cener-of-mass energy of 13 TeV Matthew Kelsey Measurements of the cross-section for producing $b$ quarks in the reaction $pp\to b\overline{b} X$ and $B$ hadron production fractions as a function of $\eta$ and transverse momentum are reported in 13 TeV collisions at the LHC with data taken by the LHCb detector. The measurements are done using semileptonic decays of $b$-flavored hadrons decaying into a ground-state charmed hadron in association with a muon. [Preview Abstract] |
Sunday, January 29, 2017 4:42PM - 4:54PM |
M12.00007: Quarks, gluons, and color are sufficient, but are they necessary II David Bartlett The 25th anniversary of the death of John Stewart Bell, was marked by lively discussion in Physics Today. This activity spurred me to consider the quark as one of Bell’s ugly “hidden variables” which can be discarded[J16.00008,April APS, 2016]. Here I extend comments on topics that are usually thought to be settled. These include CP-violation in KLong decay and “quantum spookiness” in B-decays. Apparently, the simple reaction e+ e- goes to ” anything + anything bar” misses essential hadronic physics. The $psi$ was indeed discovered by observing a sharp peak in the total cross section for e+e- at SLAC, but the J was found in the fragments from pp collisions at Brookhaven. Similarly, the parity of the D-meson was determined in a particle reconstruction by an LBL-SLAC group. They analyzed the Dalitz plot of the K$pi$$pi$ in fragments at SPEAR and found “Evidence for Parity Nonconservation in the Decays of the Narrow states near 1.87 GeV/c$^2$ [J. E. Wiss et al (1976)]. The authors did not mention quarks at all. Finally, the parity of the B-meson may be relevant to the exotic “charmonium” states observed in fragments at the B-factories. Unfortunately, the parity of the B cannot currently be determined independently of the quark model[PDG-2014, B+/-,top page 51]. [Preview Abstract] |
Sunday, January 29, 2017 4:54PM - 5:06PM |
M12.00008: Constraining the Sea Quark Distributions Through W$^\pm$ Cross Section Ratio Measurements at STAR Matthew Posik Over the past several years parton distribution functions (PDFs) have become more precise, however there are still regions where more data are needed to help constrain global PDF extractions. One such distribution is the sea quark distribution near the valence region (Bjorken-x $\approx$ 0.1 - 0.3), in particular the $\bar{d}/\bar{u}$ distribution which seems to suggest possible non-perturbative effects playing a role in this region. The charged W cross section ratio (W$^+$/W$^-$) is sensitive to the unpolarized $u,\;d,\;\bar{u},$ and $\bar{d}$ quark distributions at large $Q^2$ (set by the $W$ mass). Through proton+proton collisions, the STAR experiment at RHIC, is well equipped to measure the e$^{\pm}$ leptonic decays of W$^{\pm}$ bosons in the mid-rapidity range $\left(|\eta| \leq 1 \right)$ at $\sqrt{s}$ = 500/510 GeV. At these kinematics STAR is sensitive to quark distributions near Bjorken-x of 0.16. RHIC runs from 2011 through 2013 have collected about 350 pb$^{-1}$ of integrated luminosity, and a 2017 run is expected to provide an additional 400 pb$^{-1}$. Presented here are preliminary results for the 2011-2012 W charged cross section ratios ($\sim$100pb$^{-1}$), and an update on the 2013 charged W cross section analysis ($\sim$250 pb$^{-1}$). [Preview Abstract] |
Sunday, January 29, 2017 5:06PM - 5:18PM |
M12.00009: Search for decays Bs -> etaprime eta and Bs -> etaprime pi0 in Belle data Anthony Zummo, Vladimir Savinov We search for the decays $B_s \to \eta^\prime \eta$ and $B_s \to \eta^\prime \pi^0$ using $121.4 {\rm ~fb^{-1}}$ of data collected at the $\Upsilon(5S)$ resonance with the Belle detector at the KEKB asymmetric-energy electron-positron collider. These decays are suppressed in the Standard Model of particle physics and proceed through $b \to u$ and $b \to s$ transitions, which are sensitive to new physics. The expected branching fractions in the Standard Model are $33.5 \times 10^{-6}$ for $B_s \to \eta^\prime \eta$ and $0.12 \times 10^{-6}$ for $B_s \to \eta^\prime \pi^0$. Neither decay has been observed yet. We use Monte Carlo simulation to study Belle sensitivity to these decays. We report the current status of our investigations to provide the best sensitivity to discovering these decays in the existing data. [Preview Abstract] |
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