To say that this is the best book on the quantum theory of fields is no praise, since to my knowledge it is the only book on this subject But it is a very good and most useful book The original was written in German and appeared in 1942 This is a translation with some minor changes A few remarks have been added, concerning meson theory and nuclear forces, also footnotes referring to modern work in this field, and finally an appendix on the symmetrization of the energy momentum tensor according to Belinfante Quantum Theory of Fields Prof Gregor Wentzel Translated from the German by Charlotte Houtermans and J M Jauch Pp ix + 224, (New York and London: Interscience Publishers, Inc, 1949) 36s

Quantum Theory of Fields

The hidden-charm pentaquark and tetraquark states

A large number of experimental discoveries especially in the heavy quarkonium sector that did not at all fit to the expectations of the until then very successful quark model led to a renaissance of hadron spectroscopy Among various explanations of the internal structure of these excitations, hadronic molecules, being analogues of light nuclei, play a unique role since for those predictions can be made with controlled uncertainty We review experimental evidences of various candidates of hadronic molecules, and methods of identifying such structures Nonrelativistic effective field theories are the suitable framework for studying hadronic molecules, and are discussed in both the continuum and finite volumes Also pertinent lattice QCD results are presented Further, we discuss the production mechanisms and decays of hadronic molecules, and comment on the reliability of certain assertions often made in the literature

Hadronic molecules

The T2K experiment is a long-baseline neutrino oscillation experiment Its main goal is to measure the last unknown lepton sector mixing angle {\theta}_{13} by observing {\nu}_e appearance in a {\nu}_{\mu} beam It also aims to make a precision measurement of the known oscillation parameters, {\Delta}m^{2}_{23} and sin^{2} 2{\theta}_{23}, via {\nu}_{\mu} disappearance studies Other goals of the experiment include various neutrino cross section measurements and sterile neutrino searches The experiment uses an intense proton beam generated by the J-PARC accelerator in Tokai, Japan, and is composed of a neutrino beamline, a near detector complex (ND280), and a far detector (Super-Kamiokande) located 295 km away from J-PARC This paper provides a comprehensive review of the instrumentation aspect of the T2K experiment and a summary of the vital information for each subsystem

The T2K Experiment

Chiral dynamics of the two /Λ(1405) states

Computer simulation of inclusive pion nuclear reactions

The $s-$wave meson-baryon scattering is analyzed for the strangeness $S=-1$ and isospin I=0 sector in a Bethe-Salpeter coupled channel formalism incorporating Chiral Symmetry. Four channels have been considered: $\pi \Sigma$, $\bar K N$, $\eta \Lambda$ and $K \Xi$. The required input to solve the Bethe-Salpeter equation is taken from lowest order Chiral Perturbation Theory in a relativistic formalism. There appear undetermined low energy constants, as a consequence of the renormalization of the amplitudes, which are obtained from fits to the $\pi\Sigma\to\pi\Sigma$ mass-spectrum, to the elastic $\bar K N \to \bar K N$ and $ \bar K N\to \pi \Sigma$ $t$--matrices and to the $ K^- p \to \eta \Lambda$ cross section data. The position and residues of the complex poles in the second Riemann Sheet of the scattering amplitude determine masses, widths and branching ratios of the $S_{01}-$ $\Lambda$(1405) and $-\Lambda$(1670) resonances, in reasonable agreement with experiment. A good overall description of data, from $\pi \Sigma$ threshold up to 1.75 GeV, is achieved despite the fact that three-body channels have not been explicitly included.

S = − 1 meson-baryon unitarized coupled channel chiral perturbation theory and the S 01 resonances Λ(1405) and -Λ(1670)

Quark mass dependence of s-wave baryon resonances

We study charmed baryon resonances that are generated dynamically within a unitary meson-baryon coupled-channel model that treats the heavy pseudoscalar and vector mesons on equal footing as required by heavy-quark symmetry. It is an extension of recent SU(4) models with t-channel vector-meson exchanges to an SU(8) spin-flavor scheme, but differs considerably from the SU(4) approach in how the strong breaking of the flavor symmetry is implemented. Some of our dynamically generated states can be readily assigned to recently observed baryon resonances, while others do not have a straightforward identification and require the compilation of more data as well as an extension of the model to d-wave meson-baryon interactions and p-wave coupling in the neglected s- and u-channel diagrams. Of several

/pdf/s-wave-charmed-baryon-resonances-from-a-coupled-channel-1fvaj7e4r0.pdf

s-wave charmed baryon resonances from a coupled-channel approach with heavy quark symmetry

We study charmed and strange baryon resonances that are generated dynamically by a unitary baryon-meson coupled-channel model which incorporates heavy-quark spin symmetry. This is accomplished by extending the SU(3) Weinberg-Tomozawa chiral Lagrangian to SU(8) spin-flavor symmetry plus a suitable symmetry breaking. The model produces resonances with negative parity from s-wave interaction of pseudoscalar and vector mesons with 1/2(+) and 3/2(+) baryons. Resonances in all the isospin, spin, and strange sectors with one, two, and three charm units are studied. Our results are compared with experimental data from several facilities, such as the CLEO, Belle or BABAR collaborations, as well as with other theoretical models. Some of our dynamically-generated states can be readily assigned to resonances found experimentally, while others do not have a straightforward identification and require the compilation of more data and also a refinement of the model. In particular, we identify the Xi(c)(2790) and Xi(c)(2815) resonances as possible candidates for a heavy-quark spin symmetry doublet.

Carmen Garcia-Recio

Papers

Computer simulation of inclusive pion nuclear reactions

S = − 1 meson-baryon unitarized coupled channel chiral perturbation theory and the S 01 resonances Λ(1405) and -Λ(1670)

Quark mass dependence of s-wave baryon resonances

s-wave charmed baryon resonances from a coupled-channel approach with heavy quark symmetry

Charmed and strange baryon resonances with heavy-quark spin symmetry