Light Hadron Spectroscopy: Theory and Experiment

Rapporteur talk at the Lepton-Photon Conference, Rome, July 2001: reviewing the evidence and strategies for understanding scalar mesons, glueballs and hybrids, the gluonic Pomeron and the interplay of heavy flavours and light hadron dynamics. Dedicated to the memory of Nathan Isgur, long-time collaborator and friend, whose original ideas in hadron spectroscopy formed the basis for much of the talk.Comment: to be published in "Lepton Photon 2001 Conference Proceedings" (World Scientific Publishing), 19 pages with 6 figure

Transitions and progress: teachers' views of progress in attainment of pupils age 5-10

There has been a longstanding concern in England and Wales with the year on year progress made by pupils, but particularly at times of change, such as transfer from primary to secondary school at age 11. In Coalton, a former mining town in the North of England, a five year UK government funded initiative known as Charter for Transition has been put in place to try to overcome some of these difficulties and improve the learning opportunities for pupils aged 5-16. The programme takes place over a 5-year period in various stages, but in this paper we make use of data from the first two years. The research team examines the viewpoints of teachers from schools that were receiving additional support in their efforts to raise achievement in phase one and the pilot phase of the project about what they saw as the main benefits of this work. We present the beginnings of our exploration of teachers’ judgements of this work, and what they saw as the difficulties with associating the project with pupil attainment.</p

Nuclear Shadowing in the Structure Function F3(x)F_3(x)

Nuclear modification of the structure function $F_3$ is investigated. Although it could be estimated in the medium and large $x$ regions from the nuclear structure function $F_2^A$, it is essentially unknown at small $x$. The nuclear structure function $F_3^A$ at small $x$ is investigated in two different theoretical models: a parton-recombination model with $Q^2$ rescaling and an aligned-jet model. We find that these models predict completely different behavior at small $x$: {\it antishadowing} in the first parton model and {\it shadowing} in the aligned-jet model. Therefore, studies of the ratio $F_3^A/F_3^D$ at small $x$ could be useful in discriminating among different models, which produce similar shadowing behavior in the structure function $F_2$. We also estimate currently acceptable nuclear modification of $F_3$ at small $x$ by using $F_2^A/F_2^D$ experimental data and baryon-number conservation.Comment: 10 pages, Latex, Figs.1 and 2 are not included, Complete postscript file including the figures is available at ftp://ftp.cc.saga-u.ac.jp/pub/paper/riko/quantum1/saga-he-78.ps.gz or at http://www.cc.saga-u.ac.jp/saga-u/riko/physics/quantum1/structure.htm

Calculating Hyperfine Couplings in Large Ionic Crystals Containing Hundreds of QM Atoms: Subsystem DFT is the Key

We present an application of the linear scaling Frozen Density Embedding (FDE) formulation of subsystem DFT to the calculation of isotropic hyperfine coupling constants (hfccs) of atoms belonging to a guanine radical cation embedded in a guanine hydrochloride monohydrate crystal. The model systems considered range from an isolated guanine to a 15,000 atom QM/MM cluster where the QM region is comprised of 36 protonated guanine cations, 36 chlorine anions and 42 water molecules. Our calculations show that the embedding effects of the surrounding crystal cannot be reproduced neither by small model systems nor by a pure QM/MM procedure. Instead, a large QM region is needed to fully capture the complicated nature of the embedding effects in this system. The unprecedented system size for a relativistic all-electron isotropic hfccs calculation can be approached in this work because the local nature of the electronic structure of the organic crystals considered is fully captured by the FDE approach

Epsilon Indi Ba/Bb: the nearest binary brown dwarf

We have carried out high angular resolution near-infrared imaging and low-resolution (R~1000) spectroscopy of the nearest known brown dwarf, Eps Indi B, using the ESO VLT NAOS/CONICA adaptive optics system. We find it to be a close binary (as also noted by Volk et al. 2003) with an angular separation of 0.732 arcsec, corresponding to 2.65AU at the 3.626pc distance of the Eps Indi system. In our discovery paper (Scholz et al. 2003), we concluded that Eps Indi B was a ~50Mjup T2.5 dwarf: our revised finding is that the two system components (Eps Indi Ba and Eps Indi Bb) have spectral types of T1 and T6, respectively, and estimated masses of 47 and 28Mjup, respectively, assuming an age of 1.3Gyr. Errors in the masses are +/-10 and +/-7Mjup, respectively, dominated by the uncertainty in the age determination (0.8-2Gyr range). This uniquely well-characterised T dwarf binary system should prove important in the study of low-mass, cool brown dwarfs. The two components are bright and relatively well-resolved: Eps Indi B is the only T dwarf binary in which spectra have been obtained for both components. They have a well-established distance and age. Finally, their orbital motion can be measured on a fairly short timescale (nominal orbital period 15 yrs), permitting an accurate determination of the true total system mass, helping to calibrate brown dwarf evolutionary models.Comment: Accepted for publication by Astronomy & Astrophysics main journal. This replacement version includes minor changes made following comments by the referee, along with a reworking of the photometric data and derived quantities using 2MASS catalogue photometry as the basis, with only a minor impact on the final result

Mixing of scalar tetraquark and quarkonia states in a chiral approach

A chiral invariant Lagrangian describing the tetraquark-quarkonia interaction is considered at the leading and subleading order in the large-$N_{c}$ expansion. Spontaneous chiral symmetry breaking generates mixing of scalar tetraquark and quarkonia states and non-vanishing tetraquark condensates. In particular, the mixing strength is related to the decay strengths of tetraquark states into pseudoscalar mesons. The results show that scalar states below 1 GeV are mainly four-quark states and the scalars between 1 and 2 GeV quark-antiquark states, probably mixed with the scalar glueball in the isoscalar sector.Comment: 30 pages, 3 figures, 6 tables, to appear in Phys. Rev.

The First Direct Distance and Luminosity Determination for a Self-Luminous Giant Exoplanet: The Trigonometric Parallax to 2MASS1207334-393254Ab

We present the first trigonometric parallax and distance for a young planetary mass object. A likely TW Hya cluster member, 2MASSW J1207334-393254Ab (hereafter 2M1207Ab) is an M8 brown dwarf with a mid to late L type planetary mass companion. Recent observations of spectral variability have uncovered clear signs of disk accretion and outflow, constraining the age of the system to <10 Myr. Because of its late spectral type and the clearly youthful nature of the system, 2M1207b is very likely a planetary mass object. We have measured the first accurate distance and luminosity for a self-luminous planetary mass object. Our parallax measurements are accurate to <2 mas (1sigma) for 2M1207Ab. With 11 total epochs of data taken from January 2006 through April 2 007 (475 images for 2M1207Ab), we determine a distance of 58.8+-7.0 pc (17.0{+2.3}{-1.8} mas, 1.28sigma) to 2M1207Ab and a calculated luminosity of 0.68-2.2x10^-5 Lsun for 2M1207b. Hence 2M1207Ab is a clear member of the TW Hya cluster in terms of its distance, proper motions, and youthful nature. However, as previously noted by Mohanty and co-workers, 2M1207b's luminosity appears low compared to its temperature according to evolutionary models.Comment: 12 pages, 3 figures, accepted to ApJ Letter