In 2003 the Belle collaboration announced the discovery of the X(3872) particle. This was confirmed shortly thereafter by the CDF, D0 and BaBar collaborations, and later by the LHCb collaboration. Based on the decay modes that have been observed to date, it is clear that this particle is a hadron, that is, a composite particle that experiences the strong nuclear force. The X(3872) was found within a family of well understood hadrons called charmonia. Interestingly, it is quite difficult to interpret the X(3872) as a charmonium state. For this reason it has been widely speculated that the X(3872) cannot be understood in terms of the quark model, unlike the vast majority of hadrons observed to date. Such hitherto unobserved particles are called exotic hadrons. Since the discovery of the X(3872), many similarly anomalous charmonium-like particles have been discovered. As would be expected, some unanticipated hadrons have also been found in the closely related bottomonium spectrum. These particles are collectively referred to as heavy quarkonium-like. Evidence is growing that at least some of these particles are exotic hadrons. If confirmed, this would have dramatic implications for our understanding of the strong nuclear force. A major experimental and theoretical effort is now underway in the field of hadron spectroscopy to determine the identities of the heavy quarkonium-like states. In order to investigate the possibility that some of these states could be exotic hadrons, theoretical calculations are needed to firmly establish their properties. One of the main arguments for the existence of exotic hadrons is that they are predicted by the fundamental theory of the strong interaction, Quantum Chromodynamics (QCD). Therefore it is desirable to predict the properties of exotic hadrons using a theoretical approach that is firmly based in QCD. One such method is QCD sum rules (QSR). The research presented here uses the QSR technique to study exotic hadrons. There are several themes in this work. First is the use of QSR to predict the masses of exotic hadrons that may exist among the heavy quarkonium-like states. The second theme is the application of sophisticated loop integration methods in order to obtain more complete theoretical results. These in turn can be extended to higher orders in the perturbative expansion in order to predict the properties of exotic hadrons more accurately. The third theme involves developing a renormalization methodology for these higher order calculations. This research has implications for the Y(3940), X(3872), Zc(3895), Yb(10890), Zb(10610) and Zb(10650) particles, thereby contributing to the ongoing effort to understand these and other heavy quarkonium-like states.

This thesis presents the first measurement of the d*(2380) (hexaquark) electromagnetic coupling, extracted from the deuteron photodisintegration (~γd → d* → ~np) reaction. The experiment was carried out at the Mainzer Microtron (MAMI) facility in the Institut für Kernphysik in Mainz, Germany. A racetrack microtron at the MAMI facility provided a 1557 MeV longitudinally polarised electron beam. This electron beam was directed onto a thin radiator to produce a bremsstrahlung photon beam. Diamond and amorphous (metallic) radiators were used to produce linearly and circularly polarised photons respectively. The produced bremsstrahlung photon beam was energy 'tagged' with a resolution of ~4 MeV over the photon-energy range of 150-1400 MeV using the Glasgow Photon Tagger. The tagged photons were incident on a 10 cm long liquid deuterium target. This target was surrounded by a new nucleon recoil polarimeter apparatus and placed within the Crystal Ball calorimeter at MAMI. An array of PbWO4 and BaF2 detectors (TAPS) was used to provide calorimetry at forward angles. The newly constructed large acceptance recoil polarimeter measures the polarisation of the nucleons in the final state. The combination of this new apparatus with the polarised photon beam facility gives access to a number of single and double polarisation observables. The photon beam asymmetry, Σ, and the double polarisation observable, Cx', were examined in measurements of the reaction d(→γ,→n→p) over a large range of energies with a close to full angular coverage. The observable Cx' is determined for the neutron produced in deuteron photodisintegration for the first time. The new data constrains mechanisms of deuteron photodisintegration and assesses the existence and contribution of the d*(2380) resonance.

No description available.

京都大学 / 0048 / 新制・課程博士 / 博士(理学) / 甲第21558号 / 理博第4465号 / 新制||理||1641(附属図書館) / 京都大学大学院理学研究科物理学・宇宙物理学専攻 / (主査)教授 大西 明, 教授 青木 慎也, 教授 田中 貴浩 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DFAM

No description available.

For the anti-charmed pentaquark state with and without strangeness a QCD sum rule analysis, which is one of the nonperturbative approaches, is presented. For this purpose we employ pentaquark currents with and without strangeness, with two different current for each case. To refine the sum rules we also consider the DN continuum contribution in our analysis since this procedure is important to identify the signal of the pentaquark state. While the sum rules for most of the currents are either non-convergent or dominated by the DN continuum, the one for the non-strange pentaquark current composed of two diquarks and an antiquark, is convergent and has a structure consistent with a positive parity pentaquark state after subtracting out the DN continuum contribution. Arguments are presented on the similarity between the result of the present analysis and that based on the constituent quark models, which predict more stable pentaquark states when the antiquark is heavy.