G. Alverson,“) W. F. Baker,@lG. Ballocchi,@) R. Benson,‘“D. Berg,@) S. Blusk,@) C. Bromberg,‘“) D. Brown,(B) D. Carey,‘2) T. Chand,‘?) C. Chandlee,‘3) B. C. Choudhary,c7) W. H. Chung,@’ L. de Barbara,@) W. Desoi,‘3) W. Dlugosz,‘l) J. Dunlea,‘3) S. Ease,@) E. Engels, Jr.J5) W. Faissler,ol G. Fanourakis,@) T. Ferbel,@) D. Garelicka(‘) G. Ginther,@) G. Glass,o) M. Glaubman,“) P. Gutierrez,‘3) K. Hartman,@) J. Huston,‘@C. Johnstone,@) V. Kapoor,(7) I. Kourbanis,“) A. Lanaro,@) C. Lirakis,“) F. Lobkowicz,@) P. Lukens,@) S. Mani,‘mA. Maul,@) J. Mansour,@) R. Miller,@) C. A. Nelson, Jr., (*)B. Oh,@) D. Orris,‘s) E. Pothier,“)E. Prebys,@’ B. M. Rajaram,“) R. Roser,(3) K. RuddickJ4) P. Shepard,@) R. K. Shivpuri,“)A. Sinanidis,“’ D. Skow,Q) P. Slattery,@)L. Sorrell,‘@ W. Toothacker,‘8)N. Varelas,@‘D. Weerasundara,‘5’ J. Whitmore,@) G. Wu,“)T. Yasuda,(‘)C. Yosef’)and M. Zielinski(3)

We present the results of a study of hadronic jets produced in association with direct photons and π0's at large transverse momenta in π−Be and pBe collisions at 500 GeV/c. Using primarily charged particles to characterize the properties of the recoiling jets, we compare their fragmentation and angular distributions, and their correlation with the trigger particle, for both the γ and π0 event samples. We also compare the data with QCD calculations that incorporate current parton distribution functions.Received 9 September 1993DOI:https://doi.org/10.1103/PhysRevD.49.3106©1994 American Physical Society

We present results from the initial run of Fermilab experiment E706. The data include incident pi- and p beams at 500 GeV/c on Be and Cu targets, and span the kinematic ranges of transverse momentum and rapidity of 3.5 less-than-or-equal-to p(T) less-than-or-equal-to 10 GeV/c and -0.7 less-than-or-equal-to y(c.m.) less-than-or-equal-to 0.7, respectively. We have measured cross sections for pi0 and direct-photon production, as well as the eta/pi0 production ratio. Rom the data on Be and Cu, we have extracted the nuclear dependence of pi0 production, parametrized as A(alpha). The cross sections are compared with next-to-leading-log QCD predictions for different choices of the QCD momentum scales and several sets of paxton distribution functions.

We present new measurements of ${\ensuremath{\pi}}^{0}$ production at high transverse momenta (${p}_{T}$) for ${\ensuremath{\pi}}^{\ensuremath{-}}$ and $p$ interactions on Be and Cu targets at 500 GeV/c. The observed dependence of the yields as a function of ${p}_{T}$ and rapidity ($y$) is compared with expectations from leading-log QCD over a kinematic range in which the inclusive cross sections fall by more than 4 order of magnitude.

We present new measurements of pi-0 production at high transverse momenta (p(T)) for pi- and p interactions on Be and Cu targets at 500 GeV/c. The observed dependence of the yields as a function of p(T) and rapidity (y) is compared with expectations from leading-log QCD over a kinematic range in which the inclusive cross sections fall by more than 4 order of magnitude.

We report new measurements of inclusive direct photon production at high transverse momenta (p(T)) for pi- and p-interactions on Be at 500 Gev/c. The yields as a function Of p(T) and rapidity (y) are in good agreement with expectations from next-to-leading-log QCD calculations employing recently extracted quark and gluon structure functions.

The design, construction and testing of X-Y tracking modules for a silicon microstrip vertex detector for use in Fermilab experiment E706 is discussed. A successful adaptation of various technologies, essential for instrumenting this class of detectors at a university laboratory is described. Emphasis is placed on considerable cost reduction, design flexibility and more rapid turnover with a view toward larger detectors for the future.

Using data on coherent production of π+π+π- systems in π+ collisions with nuclei we exclude the existence ofJPC=1−+,I=1, exotic hybrid mesons with masses below 1.5 GeV and widths greater than 20 MeV, provided that their primary coupling is to πρ systems. Hybrid states with just such properties have recently been predicted from arguments based on QCD sum rules. Our experimental limit is based on Primakoff production of these states, and on an argument using vector dominance to relate their radiative widths to πρ channels. There has been increasing interest of late in the existence of hybrid states, which, in the case of mesons, contain a valence gluon in addition to aq\(\bar q\) pair in a color-octet state [1–5]. The pursuit of spectroscopic gluon degrees of freedom has been strongly motivated by the general QCD picture of hadrons, as well as by many specific calculations based on QCD sum rules, lattice simulations, and more phenomenological approaches such as QCD-bag models. Although much effort, both thoretical and experimental, has been devoted to the spectroscopy of glueballs, for which several candidates exist [6], it has also been realized that hybrid states may be as amenable to discovery, and perhaps less ambiguous to interpretation.

We present the results of new precision measurements of the radiative decay width, total width, and mass of the ${\ensuremath{\rho}}^{+}$ meson. These parameters are, respectively, 59.8\ifmmode\pm\else\textpm\fi{}4.0 keV, 0.150\ifmmode\pm\else\textpm\fi{}0.005 GeV, and 0.771\ifmmode\pm\else\textpm\fi{}0.004 GeV, and were extracted from data obtained on the coherent production of ${\ensuremath{\rho}}^{+}$ in 200-GeV/c ${\ensuremath{\pi}}^{+}$ interactions with nuclear targets.

We have measured the coherent nuclear production of low-mass ${K}^{+}\ensuremath{\omega}$ systems in ${K}^{+}A$ collisions at 202.5 GeV. Results for carbon, copper, and lead targets are similar to those found for ${\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$ production in ${\ensuremath{\pi}}^{+}A$ reactions at the same energy.

We have carried out a partial-wave analysis (PWA) of three-pion systems produced in the coherent dissociation of ${\ensuremath{\pi}}^{+}$ mesons on nuclear targets. The data have been analyzed for copper and lead targets at an incident ${\ensuremath{\pi}}^{+}$ energy of 202.5 GeV. This PWA provides further evidence for resonant contributions to ${J}^{P}={1}^{+} \mathrm{and} {0}^{\ensuremath{-}}$ waves at $3\ensuremath{\pi}$ masses below 1.5 GeV, which can be plausibly identified with ${A}_{1}$ and ${\ensuremath{\pi}}^{\ensuremath{'}}$ mesons. The contribution from electromagnetic production of the ${A}_{2}$ has also been extracted, and an estimate for Coulomb production and radiative width of the ${A}_{1}$ has been obtained.

We present evidence for elastic pion Compton scattering as observed via the Primakoff process on nuclear targets. We find production cross sections for ${\ensuremath{\pi}}^{\ensuremath{-}}A\ensuremath{\rightarrow}{\ensuremath{\pi}}^{\ensuremath{-}}\ensuremath{\gamma}A$ on lead and copper of 0.249\ifmmode\pm\else\textpm\fi{}0.027 and 0.029\ifmmode\pm\else\textpm\fi{}0.006 mb, respectively, in agreement with the values expected from the one-photon-exchange mechanism of 0.268\ifmmode\pm\else\textpm\fi{}0.018 and 0.035\ifmmode\pm\else\textpm\fi{}0.004 mb in the region of our experimental acceptance. This reaction provides a clean test of the Primakoff formalism.

Based on theoretical comparison of ${\ensuremath{\pi}}^{+}$ elastic Compton scattering with data on production of ${\ensuremath{\pi}}^{+}\ensuremath{\gamma}$ systems in ${\ensuremath{\pi}}^{+}Z\ensuremath{\rightarrow}{\ensuremath{\pi}}^{+}\ensuremath{\gamma}Z$ reactions, we present additional evidence of the veracity of the Primakoff formalism at the \ensuremath{\lesssim} 10% level of uncertainty.

Using data on the coherent production of ${\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$ systems in ${\ensuremath{\pi}}^{+}$ collisions with nuclei, we have extracted an estimate for the radiative partial width of the ${A}_{1}$. The rate for ${{A}_{1}}^{+}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{+}\ensuremath{\gamma}$ is 640\ifmmode\pm\else\textpm\fi{}246 keV, which is a factor of about 2-3 below the value expected on the basis of predictions from quark models and from vector dominance ideas.

Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Icon Share Twitter Facebook Reddit LinkedIn Tools Icon Tools Reprints and Permissions Cite Icon Cite Search Site Citation D. Berg, C. Chandlee, S. Cihangir, T. Ferbel, J. Huston, T. Jensen, F. Lobkowicz, M. McLaughlin, T. Ohshima, P. Slattery, P. Thompson, M. Zielinski, B. Collick, S. Heppelmann, Y. Makdisi, M. Marshak, E. Peterson, K. Ruddick, M. Shupe, J. Biel, A. Jonckheere, C. A. Nelson; Radiative decays of low lying mesons. AIP Conf. Proc. 15 May 1984; 113 (1): 157–167. https://doi.org/10.1063/1.34458 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentAIP Publishing PortfolioAIP Conference Proceedings Search Advanced Search |Citation Search

We have measured the coherent nuclear production of ${\ensuremath{\pi}}^{+}\ensuremath{\omega}$ systems at 202.5 GeV. This final state is dominated by the ${B}^{+}(1235)$ meson with a measured mass and full width of 1.271 \ifmmode\pm\else\textpm\fi{} 0.011 GeV and 0.232 \ifmmode\pm\else\textpm\fi{} 0.029 GeV, respectively. A radiative width of 230 \ifmmode\pm\else\textpm\fi{} 60 keV was extracted for the process ${B}^{+}(1235)\ensuremath{\rightarrow}{\ensuremath{\pi}}^{+}\ensuremath{\gamma}$.