Nucleon-Deuteron Scattering from an Effective Field Theory

We use an effective field theory to compute low-energy nucleon-deuteron scattering. We obtain the quartet scattering length using low energy constants entirely determined from low-energy nucleon-nucleon scattering. We find $a_{th}=6.33$ fm, to be compared to $a_{exp}=6.35\pm 0.02$ fm.Comment: 8 pages, Latex, epsfig, figures include

Effect of 22(S), 23(S)-Homobrassinolide on Adventitious Root Formation in Grape Rootstocks

In recent times, brassinosteroids have been identified as a group of hormones that regulate plant growthand development. They affect plant development from seed germination to senescence. The aim of thisresearch was to study the effects of brassinosteroids on the rooting of three American grapevine rootstocks(1103 Paulsen, 110 Richter and 99 Richter) used frequently to produce grafted grapevines. Rootstockcuttings were dipped for 10 minutes into five different concentrations of 22(S), 23(S)-homobrassinolide andplanted into a peat-perlite mixture. Data such as fresh and dry root weight, root number and developmentlevel were collected and assessed. Some shoot growth features were also determined. The results showedthat the grapevine rootstocks with the most significant response in improved root and shoot growth were1103 Paulsen, followed by 110 Richter. Root development level was influenced by both the rootstock andthe concentrations of the substance. The lowest concentration, 0.05 ppm, induced more root numbers in1103 Paulsen, while 0.15 ppm resulted in the highest number of roots in 99 Richter. A statistical analysis ofthe data revealed a significant difference between root development and shoot growth

On the Origin of Light Dark Matter Species

TeV-mass dark matter charged under a new GeV-scale gauge force can explain electronic cosmic-ray anomalies. We propose that the CoGeNT and DAMA direct detection experiments are observing scattering of light stable states -- "GeV-Matter" -- that are charged under this force and constitute a small fraction of the dark matter halo. Dark higgsinos in a supersymmetric dark sector are natural candidates for GeV-Matter that scatter off protons with a universal cross-section of 5 x 10^{-38} cm^2 and can naturally be split by 10-30 keV so that their dominant interaction with protons is down-scattering. As an example, down-scattering of an O(5) GeV dark higgsino can simultaneously explain the spectra observed by both CoGeNT and DAMA. The event rates in these experiments correspond to a GeV-Matter abundance of 0.2-1% of the halo mass density. This abundance can arise directly from thermal freeze-out at weak coupling, or from the late decay of an unstable TeV-scale WIMP. Our proposal can be tested by searches for exotics in the BaBar and Belle datasets.Comment: 31 text pages, 4 figures, revision includes corrected Germanium quenching factor and clarified text in Sec.

The Nucleon Anapole Form Factor in Chiral Perturbation Theory to Sub-leading Order

The anapole form factor of the nucleon is calculated in chiral perturbation theory to sub-leading order. This is the lowest order in which the isovector anapole form factor does not vanish. The anapole moment depends on counterterms that reflect short-range dynamics, but the momentum dependence or the form factor is determined by pion loops in terms of parameters that could in principle be fixed from other processes. If these parameters are assumed to have natural size, the sub-leading corrections do not exceed ~ 30% at momentum Q ~ 300 MeV.Comment: 11 pages, 6 figures, epsf.sty, submitted to Phys. Lett

Periodic orbit effects on conductance peak heights in a chaotic quantum dot

We study the effects of short-time classical dynamics on the distribution of Coulomb blockade peak heights in a chaotic quantum dot. The location of one or both leads relative to the short unstable orbits, as well as relative to the symmetry lines, can have large effects on the moments and on the head and tail of the conductance distribution. We study these effects analytically as a function of the stability exponent of the orbits involved, and also numerically using the stadium billiard as a model. The predicted behavior is robust, depending only on the short-time behavior of the many-body quantum system, and consequently insensitive to moderate-sized perturbations.Comment: 14 pages, including 6 figure

Discovering New Light States at Neutrino Experiments

Experiments designed to measure neutrino oscillations also provide major opportunities for discovering very weakly coupled states. In order to produce neutrinos, experiments such as LSND collide thousands of Coulombs of protons into fixed targets, while MINOS and MiniBooNE also focus and then dump beams of muons. The neutrino detectors beyond these beam dumps are therefore an excellent arena in which to look for long-lived pseudoscalars or for vector bosons that kinetically mix with the photon. We show that these experiments have significant sensitivity beyond previous beam dumps, and are able to partially close the gap between laboratory experiments and supernovae constraints on pseudoscalars. Future upgrades to the NuMI beamline and Project X will lead to even greater opportunities for discovery. We also discuss thin target experiments with muon beams, such as those available in COMPASS, and show that they constitute a powerful probe for leptophilic PNGBs.Comment: 32 text pages, 5 figures, 4 table

The Three-Boson System with Short-Range Interactions

We discuss renormalization of the non-relativistic three-body problem with short-range forces. The problem is non-perturbative at momenta of the order of the inverse of the two-body scattering length. An infinite number of graphs must be summed, which leads to a cutoff dependence that does not appear in any order in perturbation theory. We argue that this cutoff dependence can be absorbed in one local three-body force counterterm and compute the running of the three-body force with the cutoff. This allows a calculation of the scattering of a particle and the two-particle bound state if the corresponding scattering length is used as input. We also obtain a model-independent relation between binding energy of a shallow three-body bound state and this scattering length. We comment on the power counting that organizes higher-order corrections and on relevance of this result for the effective field theory program in nuclear and molecular physics.Comment: 24 pages, RevTex, 15 PS figures included with epsf.st

Nonlocality of the NN interaction in an effective field theory

We investigate low energy nucleon dynamics in the effective field theory (EFT) of nuclear forces. In leading order of the two-nucleon EFT we show that nucleon dynamics is governed by the generalized dynamical equation with a nonlocal-in-time interaction operator. This equation is shown to open new possibilities for applying the EFT approach to the description of low energy nucleon dynamics.Comment: 13 pages, 4 figures, REVTeX

Effective Theory of the Triton

We apply the effective field theory approach to the three-nucleon system. In particular, we consider S=1/2 neutron-deuteron scattering and the triton. We show that in this channel a unique nonperturbative renormalization takes place which requires the introduction of a single three-body force at leading order. With one fitted parameter we find a good description of low-energy data. Invariance under the renormalization group explains some universal features of the three-nucleon system ---such as the Thomas and Efimov effects and the Phillips line--- and the origin of SU(4) symmetry in nuclei.Comment: 16 pages, Latex, 7 PS figures included with epsf.sty, discussion and references added, conclusions unchange