75 Matching Results

Search Results

Advanced search parameters have been applied.

The scalar glueball mass in Regge phenomenology

Description: The author shows that linear Regge trajectories for mesons and glueballs, and the cubic mass spectrum associated with them, determine a relation between the masses of the {rho} meson and the scalar glueball, M(0{sup ++}) = 3/{radical}2 M({rho}), which implies M(0{sup ++}) = 1620 {+-} 10 MeV. He also discusses a relation between the masses of the scalar and tensor glueballs, M(2{sup ++}) = {radical}2 M(0{sup ++}), which implies M(2{sup ++}) = 2290 {+-} 15 MeV.
Date: December 1, 1998
Creator: Burakovsky, L.
Partner: UNT Libraries Government Documents Department

Hunting the Scalar Glueball: Prospects for BES III

Description: The search for the ground state scalar glueball $G_0$ isreviewed. Spin zero glueballs will have unique dynamical properties ifthe $<G_0|\overline qq>$ amplitude is suppressed by chiralsymmetry, as it is to all orders in perturbation theory: for instance,mixing of $G_0$ with $\overline qq$ mesons would be suppressed, radiative$\jp$ decay would be a filter for new physics in the spin zero channel,and the decay $G_0 \rightarrow \overline KK$ could be enhanced relativeto $G_0 \rightarrow \pi \pi$. These properties are consistent with theidentification of $f_0(1710)$ as the largely unmixed ground state scalarglueball, while recent BES data implies that $f_0(1500)$ does not containthe dominant glueball admixture. Three hypotheses are discussed: that$G_0$ is 1) predominantly $f_0(1500)$ or 2) predominantly $f_0(1710)$ or3) is strongly mixed between $f_0(1500)$ and $f_0(1710)$.
Date: September 18, 2006
Creator: Chanowitz, Michael S.
Partner: UNT Libraries Government Documents Department


Description: The authors consider glueball-(hybrid) meson mixing for the low-lying four pseudovector states. The h{sub 1}{prime}(1380) decays dominantly to K*K with some presence in {rho}{pi} and {omega}{eta}. The newly observed h{sub 1}(1600) has a D- to S-wave width ratio to {omega}{eta} which makes its interpretation as a conventional meson unlikely. They predict the decay pattern of the isopartner conventional or hybrid meson b{sub 1}(1650). A notably narrow s{bar s} partner h{sub 1}{prime}(1810) is predicted.
Date: June 1, 2000
Creator: BURAKOVSKY, L. & PAGE, P.
Partner: UNT Libraries Government Documents Department

Panel discussion on the future of hadron spectroscopy

Description: This contribution addresses two of the questions which were submitted to the panel on future developments in light hadron spectroscopy. Specifically, these were the extent to which glueball spectroscopy should be explored and how far it is appropriate to continue experimental studies of the light hadron spectrum. The authors suggest that at a minimum three particular glueball states should be identified, that hybrids should also be identified, and that experiments on hadrons should continue for as long as the theoretical community remains unable to predict their outcome.
Date: December 31, 1995
Creator: Barnes, T.
Partner: UNT Libraries Government Documents Department

Interaction of Wilson loops in the confining vacuum

Description: Nonperturbative and perturbative interaction mechanisms of Wilson loops in gluodynamics are studied within the background field formalism. The first one operates when distance between minimal surfaces of the loops is small and may be important for sea quark effects and strong decay processes. The second mechanism -- perturbative interaction in nonperturbative confining background is found to be physically dominant for all loop configurations characteristic of scattering process. It reduces to perturbative gluon exchanges at small distances, while at larger distances it corresponds to the t-channel exchange of (reggeized) glueball states. Comparison to other approaches is made and possible physical applications are discussed.
Date: April 1, 2002
Creator: Shevchenko, V.I. & Simonov, Yu. A.
Partner: UNT Libraries Government Documents Department

Triangular and Y-shaped hadrons in QCD

Description: Gauge invariant extended configurations are considered for 3 fundamental (quarks) or adjoint (gluons) particles. For 3 quarks it is proved that the only possible gauge-invariant configuration is the Y-shaped one, proposed long ago, while the triangular one proposed recently is ruled out. For adjoint sources both configurations are possible. Static potential is computed in all cases. For baryons the Y-shaped configuration leads to a significant depletion of field-strength density at the string-junction position, which decreases the effective potential slope at R {approx} 0.5 fm by 10-15%, as observed on the lattice. For adjoint sources the Y-shaped and {Delta}-shaped potentials are very close, leading to almost degenerate masses of 3--3g glueballs and odderon trajectories.
Date: March 1, 2002
Creator: Kuzmenko, D. S. & Simonov, Yu. A.
Partner: UNT Libraries Government Documents Department

Theoretical predictions for exotic hadrons

Description: In this contribution the authors discuss current theoretical expectations for the properties of light meson exotica, which are meson resonances outside the q{anti q} quark model. Specifically they discuss expectations for gluonic hadrons (glueballs and hybrids) and multiquark systems (molecules). Experimental candidates for these states are summarized, and the relevance of a TCF to these studies is stressed.
Date: December 1996
Creator: Barnes, T.
Partner: UNT Libraries Government Documents Department


Description: Lattice QCD gives reliable predictions for hybrid charmonium and multi-GeV glueball masses. Proton-antiproton annihilation may offer an excellent opportunity for the first observation of these states. There are two distinct possible programs: The search for J{sup PC}-exotic and non-J{sup PC}-exotic states. The latter program represents substantially higher cross sections and does not absolutely require partial wave analysis, two very attractive features. The program can be performed with a varying {bar p} energy &lt; 10 GeV and a fixed target.
Date: June 1, 2001
Creator: PAGE, P.R.
Partner: UNT Libraries Government Documents Department

Lattice Gauge Theory - QCD from quarks to hadrons

Description: Lattice Gauge Theory enables an ab initio study of the low-energy properties of Quantum Chromodynamics, the theory of the strong interaction. The author begins these lectures by presenting the lattice formulation of QCD, and then outline the benchmark calculation of lattice QCD, the light-hadron spectrum. He then proceeds to explore the predictive power of lattice QCD, in particular as it pertains to hadronic physics. He discusses the spectrum of glueballs, exotics and excited states, before investigating the study of form factors and structure functions. He concludes by showing how lattice QCD can be used to study multi-hadron systems, and in particular provide insight into the nucleon-nucleon interaction.
Date: June 1, 2000
Creator: Richards, D.G.
Partner: UNT Libraries Government Documents Department

VMD, the WZW Lagrangian and ChPT:The Third Mixing Angle

Description: We show that the Hidden Local Symmetry Model, supplemented with well-known procedures for breaking flavor SU(3) and nonet symmetry, provides all the information contained in the standard Chiral Perturbation Theory (ChPT) Lagrangian L{sup (0)} + L{sup (1)}. This allows to rely on radiative decays of light mesons (VP{gamma} and P{gamma}{gamma}) in order to extract some numerical information of relevance to ChPT: a value for {Lambda}{sub 1} = 0.20 {+-} 0.04, a quark mass ratio of {approx_equal} 21.2 {+-} 2.4, and a negligible departure from the Gell-Mann--Okubo mass formula. The mixing angles are {theta}{sub 8} = {minus}20.40{degree} {+-} 0.96{degree} and {theta}{sub 0} = {minus}0.05{degree} {+-} 0.99{degree}. We also give the values of all decay constants. It is shown that the common mixing pattern with one mixing angle {theta}{sub P} is actually quite appropriate and algebraically related to the {eta}/{eta}{prime} mixing pattern presently preferred by the ChPT community. For instance the traditional {theta}{sub p} is functionally related to the ChPT {theta}{sub 8} and fulfills {theta}{sub P} {approx_equal} {theta}{sub 8}/2. The vanishing of {theta}{sub 0}, supported by all data on radiative decays, gives a novel relation between mixing angles and the violation of nonet symmetry in the pseudoscalar sector. Finally, it is shown that the interplay of nonet symmetry breaking through U(3) {r_arrow} SU(3) x U(1) satisfies all requirements of the physics of radiative decays without any need for additional glueballs.
Date: March 31, 1999
Creator: O'Connell, Heath B
Partner: UNT Libraries Government Documents Department

Elusive Vector Glueball

Description: If the vector glueball {Omicron} exists in the mass range that theory suggests, its resonant production cross section can be detected in e{sup +}e{sup -} annihilation only if the decay width is very narrow ({le} a few MeV). Otherwise {Omicron} will be observed only indirectly through its mixing with {psi}{prime}. We propose a few tests of the {Omicron}-{psi}{prime} mixing for future charm factories.
Date: May 1, 2002
Creator: Suzuki, Mahiko
Partner: UNT Libraries Government Documents Department

Oddballs and a Low Odderon Intercept

Description: The authors report an odderon Regge trajectory emerging from a field theoretical Coulomb gauge QCD model for the odd signature J{sup PC} (P = C = -1) glueball states (oddballs). The trajectory intercept is clearly smaller than the pomeron and even the {omega} trajectory's intercept which provides an explanation for the nonobservation of the odderon in high energy scattering data. To further support this result we compare to glueball lattice data and also perform calculations with an alternative model based upon an exact Hamiltonian diagonalization for three constituent gluons.
Date: July 27, 2005
Creator: Llanes-Estrada, Felipe J.; U., /Madrid; Bicudo, Pedro; /Lisbon U. /Lisbon, IST; Cotanch, Stephen R. & U., /North Carolina State
Partner: UNT Libraries Government Documents Department

Chiral Suppression of Scalar Glueball Decay

Description: Because glueballs are SU(3){sub Flavor} singlets, they are expected to couple equally to u,d, and s quarks, so that equal coupling strengths to {pi}{sup +}{pi}{sup -} and K{sup +}K{sup -} are predicted. However, we show that chiral symmetry implies the scalar glueball amplitude for G{sub 0} {yields} {bar q}q is proportional to the quark mass, so that mixing with {bar s}s mesons is enhanced and decays to K{sup +}K{sup -} are favored over {pi}{sup +}{pi}{sup -}. Together with evidence from lattice calculations and from experiment, this supports the hypothesis that f{sub 0}(1710) is the ground state scalar glueball.
Date: June 10, 2005
Creator: Chanowitz, Michael S.
Partner: UNT Libraries Government Documents Department

Double Pomeron Exchange: from the ISR to the LHC

Description: I discuss Double Pomeron Exchange processes from their first observation at the CERN Intersecting Storage Rings, focusing on glueball searches, through the observations of exclusive {chi}{sub c0}, {gamma}{gamma} and di-jets at the Tevatron, to prospects at the LHC for exclusive Higgs boson production.
Date: September 1, 2010
Creator: Albrow, Michael
Partner: UNT Libraries Government Documents Department

Hunting for glueballs in electron-positron annihilation

Description: We calculate the cross section for the exclusive production of J{sup PC} = 0{sup ++} glueballs G{sub 0} in association with the J/{psi} in e{sup +}e{sup -} annihilation using the pQCD factorization formalism. The required long-distance matrix element for the glueball is bounded by CUSB data from a search for resonances in radiative {Upsilon} decay. The cross section for e{sup +}e{sup -} {yields} J/{psi} + G{sub 0} at {radical}s = 10.6 GeV is similar to exclusive charmonium-pair production e{sup +}e{sup -} {yields} J/{psi} + h for h = {eta}{sub c} and {chi}{sub c0}, and is larger by a factor 2 than that for h = {eta}{sub c}(2S). As the subprocesses {gamma}* {yields} (c {bar c}) (c {bar c}) and {gamma}* {yields} (c {bar c}) (g g) are of the same nominal order in perturbative QCD, it is possible that some portion of the anomalously large signal observed by Belle in e{sup +}e{sup -} {yields} J/{psi} X may actually be due to the production of charmonium-glueball J/{psi} G{sub J} pairs.
Date: May 1, 2003
Creator: Brodsky, Stanley; Goldhaber, Alfred Scharff & Lee, Jungil
Partner: UNT Libraries Government Documents Department

Confinement, diquarks and goldstone`s theorem

Description: Determinations of the gluon propagator in the continuum and in lattice simulations are compared. A systematic truncation procedure for the quark Dyson-Schwinger and bound state Bethe-Salpeter equations is described. The procedure ensures the flavor-octet axial- vector Ward identity is satisfied order-by-order, thereby guaranteeing the preservation of Goldstone`s theorem; and identifies a mechanism that simultaneously ensures the absence of diquarks in QCD and their presence in QCD{sup N{sub c}=2}, where the color singlet diquark is the ``baryon`` of the theory.
Date: December 31, 1996
Creator: Roberts, C.D.
Partner: UNT Libraries Government Documents Department

B {r_arrow} {eta}{prime} + X and the QCD anomaly

Description: Mechanisms for the observed large Br(B {r_arrow} {eta}{prime} +X{sub s}) are examined. The authors propose that the dominant fraction of the B {r_arrow} {eta}{prime} + X{sub s} rate is due mainly to b {r_arrow} sg{sup *}, where g{sup *} is an off-shell gluon, followed by g{sup *} {r_arrow} g{eta}{prime} via the anomalous coupling of the {eta}{prime} to two gluons. The calculated rate for B {r_arrow} {eta}{prime} + X{sub s} is in rough accord with experiment using a fairly constant glue-glue-{eta}{prime} form factor. This behavior of the form factor may be indicative of glueball dominance of the channel. Searches via the modes {eta}{prime}h{sup +}h{sup {minus}} (h={pi} or K) may be worthwhile. Charmonia contributions [i.e B {r_arrow} {eta}{sub c}, {psi} ({r_arrow}{eta}{prime} + X) + X{sub s}] can only account for at most 20% of the central value of the signal. Implications for B {r_arrow} {eta}{prime} + X{sub d} and for the corresponding {eta} modes are also given.
Date: April 1, 1997
Creator: Atwood, D. & Soni, A.
Partner: UNT Libraries Government Documents Department

Gluonic hadrons and charmless B decays

Description: Hybrid charmonium with mass {approximately} 4 GeV could be produced via a c{anti c} color-octet component in b {r_arrow} c{anti c}s. These states could be narrow and could have a significant branching ratio to light hadrons, perhaps enhanced by glueballs. Decays to gluonic hadrons could make a sizable contribution to B {r_arrow} no charm decays. Experimental signatures and search strategies are discussed.
Date: August 1, 1997
Creator: Close, F.E.; Dunietz, I.; Page, P.R.; Veseli, S. & Yamamoto, H.
Partner: UNT Libraries Government Documents Department


Description: I review the calculation of the glueball spectrum in non-supersymmetric Yang-Mills theory (in 3 and 4 dimensions) using the conjectured duality between supergravity and large N gauge theories. The glueball masses are obtained by solving the supergravity wave equations in a black hole geometry. The masses obtained this way are in unexpectedly good agreement with the available lattice data, and are much better than strong-coupling expansion results. I also show how to use a modified version of the duality to calculate the glueball mass spectrum with some of the Kaluza-Klein states of the supergravity theory decoupled from the spectrum.
Date: January 1, 2002
Partner: UNT Libraries Government Documents Department

Scalar mesons and the search for the 0{sup ++} Glueball

Description: The possibility that gluonic excitations of hadronic matter or of the QCD vacuum may exist is perhaps one of the most fascinating topics in hadron spectroscopy. Glueballs are predicted by many models; in particular present-day lattice gauge calculations require their existence. All these models agree that the lightest glueball should have scalar quantum numbers and a mass around 1.6 GeV, which corresponds to the mass region where the scalar qq[bar]-mesons are expected. Therefore mixing effects can complicate the search for the glueball. Experiments indeed show an overpopulation of states, for which many different interpretations exist. This reflects the complexity of the situation. New data from various experiments on scalar states give hints toward an interpretation of the scalar states. But, still many questions remain.
Date: October 1, 2002
Creator: Thoma, Ulrike
Partner: UNT Libraries Government Documents Department

QCD spectrum from the lattice

Description: Considerable progress has been made in the last year to derive the spectrum from QCD in the quenched approximation. I review the results for the proton to rho mass ratio and show that we are close to getting results to within 10%. I present new results for 0{sup ++} and 2{sup ++} glueballs. These results are qualitative since we do not address the question of mixing of glueballs with quark states. Finally, I give a status report on the full QCD calculations (2 flavors of dynamical Wilson fermions) being done on the Connection Machine 2. 12 refs., 3 figs.
Date: January 1, 1989
Creator: Gupta, R.
Partner: UNT Libraries Government Documents Department

New View of the QCD Phase Diagram

Description: Quarkyonic matter is confining but can have densities much larger than 3QCD. Its existence isargued in the large Nc limit of QCD and implies that there are at least three phases of QCD with greatly different bulk properties. These are a Confined Phase of hadrons, a Deconfined Phase ofquarks and gluons, and the Quarkyonic Phase. In the Quarkyonic Phase, the baryon density isaccounted for by a quasi-free gas of quarks, and the the antiquarks and gluons are confined intomesons, glueballs. Quarks near the Fermi surface also are treated as baryons. (In addition tothese phases, there is a color superconducting phase that has vastly different transport properties than the above, but with bulk properties, such as pressure and energy density, that are not greatlydifferent than that of Quarkyonic Matter.)
Date: July 9, 2009
Creator: McLerran,L.
Partner: UNT Libraries Government Documents Department

Study of B Meson Decays to ppbarh Final States

Description: B mesons are unique among well-established non-quarkonium mesons in their ability to decay into baryons. Baryonic B decays offer a wide range of interesting areas of study: they can be used to test our theoretical understanding of rare decay processes involving baryons, search for direct CP violation and study low-energy QCD. This thesis presents measurements of branching fractions and a study of the decay dynamics of the charmless three-body decays of B meson into p{bar p}h final states, where h = {pi}{sup +}, K{sup +}, K{sub S}{sup 0}, K*{sup 0} or K*{sup +}. With a sample of 232 million {Upsilon}(4S) {yields} B{bar B} events collected with the BaBar detector, we report the first observation of the B {yields} p{bar p}K*{sup 0} decay, and provide improved measurements of branching fractions of the other modes. The distribution of the three final-state particles is of particular interest since it provides dynamical information on the possible presence of exotic intermediate states such as the hypothetical pentaquark states {Theta}*{sup ++} and {Theta}{sup +}in the m{sub pK{sup +}} and m{sub pK{sub S}{sup 0}} spectra, respectively, or glueball states (such as the tensor glueball f{sub J}(2220)) in the m{sub p{bar p}} spectrum. No evidence for exotic states is found and upper limits on the branching fractions are set. An enhancement at low p{bar p} mass is observed in all the B {yields} p{bar p}h modes, and its shape is compared between the decay modes and with the shape of the time-like proton form factor. A Dalitz plot asymmetry in B {yields} p{bar p}K{sup +} mode suggests dominance of the penguin amplitude in this decay and disfavors the possibility that the low mass p{bar p} enhancement originates from the presence of a resonance below threshold (such as the recently seen baryonium candidate at 1835 MeV/c{sup 2}). We also ...
Date: March 22, 2006
Creator: Hryn'ova, Tetiana B.
Partner: UNT Libraries Government Documents Department