Generalized L\"uscher Formula in Multi-channel Baryon-Meson Scattering

L\"uscher's formula relates the elastic scattering phase shifts to the two-particle energy levels in a finite cubic box. The original formula was obtained for elastic scattering of two massive spinless particles in the center of mass frame. In this paper, we consider the case for the scattering of a spin 1/2 particle with a spinless particle in multi-channel scattering. A generalized relation between the energy of two particle system and the scattering matrix elements is established. We first obtain this relation using quantum-mechanics in both center-of-mass frame and in a general moving frame. The result is then generalized to quantum field theory using methods outlined in Ref. \cite{Hansen:2012tf}. We verify that the results obtained using both methods are equivalent up to terms that are exponentially suppressed in the box size.Comment: One reference adde

Dessecação de plantas de soja com glyphosate e qualidade das sementes armazenadas.

Sementes de cultivares convencionais de soja colhidas após dessecação química podem produzir plântulas anormais, com sintomas de fitotoxicidade que podem persistir após o armazenamento. Este trabalho objetivou avaliar a qualidade fisiológica de sementes armazenadas de soja em função da dessecação química das plantas em pré-colheita com glyphosate. Sementes de soja da cultivar convencional Conquista foram produzidas na ausência e presença de dessecação das plantas com glyphosate (na dose de 2,0 L ha-1) no estádio de maturidade fisiológica (R7). A qualidade das sementes foi avaliada logo após a colheita e aos 8 meses de armazenamento em câmara seca quanto ao teor de água, massa, germinação e vigorA qualidade das sementes de soja foi influenciada pela interação entre a aplicação do glyphosate como dessecante e o tempo de armazenamento, com exceção da condutividade elétrica, que variou somente em função do período de análise. A dessecação química das plantas ocasionou diminuição da massa e da qualidade das sementes de soja independente do período de análise; no entanto, os efeitos do armazenamento foram variáveis dependendo da avaliação. A germinação das sementes foi maior após o armazenamento devido à redução na ocorrência de fungos . A massa das sementes e sua germinação após o teste de envelhecimento acelerado foram reduzidas após 8 meses. O desenvolvimento das plântulas, tanto quanto ao comprimento total e de suas partes como a massa da matéria seca, foi reduzido pela aplicação de glyphosate em pré-colheita, mas não variou após o período de armazenamento. A dessecação química das plantas de soja com glyphosate reduz a qualidade fisiológica das sementes de soja e os sintomas de fitotoxicidade persistem mesmo após 8 meses de armazenamento

Pre-harvest desiccation with glyphosate and quality of stored soybean seeds.

ABSTRACT: Seeds from non-genetically modified soybean cultivars harvested after chemical desiccation of plants with glyphosate may produce abnormal seedlings; these may show phytotoxicity symptoms that could persist even after some time of storage due to accumulation of toxic residues. This study aimed to evaluate the quality of stored soybean seeds harvested after chemical desiccation of plants with glyphosate at R7 stage. Seeds from soybean cultivar ?Conquista? were produced with and without desiccation with glyphosate, at the dose 2.0 L ha-1, applied at physiological maturity stage. Seed quality was evaluated right after harvest and after eight months of storage by tests of moisture content, mass, germination and vigor. The experimental design was the completely randomized block with four replications. Data was submitted to variance analysis and means were compared by the Tukey test (p ≤ 0.05) as a 2 x 2 factorial. The results show deleterious effects of glyphosate used as desiccant for early harvest of soybean seeds from conventional cultivars. Accelerating plant senescence leads to production of seeds with lower germination and decreased seedling development, although the percentage of abnormal seedlings is reduced after 8 months of storage possibly due to degradation of toxic residues of glyphosate and/or derivates. RESUMO: Sementes de cultivares convencionais de soja colhidas após dessecação química das plantas com glifosato podem produzir plântulas anormais, com sintomas de fitotoxicidade que podem persistir mesmo após o armazenamento devido ao acúmulo de resíduos tóxicos. Este trabalho objetivou avaliar a qualidade de sementes armazenadas de soja colhidas após dessecação química das plantas com glifosato no estádio R7. Sementes de soja da cultivar Conquista foram produzidas com e sem dessecação das plantas com glifosato, na dose de 2,0 L ha-1, no estádio de maturidade fisiológica. A qualidade das sementes foi avaliada logo após a colheita e aos oito meses de armazenamento quanto ao teor de água, massa, germinação e vigor. O delineamento experimental foi o inteiramente casualizado, com quatro repetições. Os dados foram submetidos à análise de variância e as médias comparadas pelo teste de Tukey (p?0,05), em esquema fatorial 2 x 2. Os resultados mostram efeitos deletérios da aplicação de glifosato utilizado como dessecante para antecipação da colheita de sementes de soja de cultivares convencionais. A aceleração da senescência das plantas resulta na produção de sementes com menor germinação e reduzido desenvolvimento de plântulas, apesar de a porcentagem de plântulas anormais ser reduzida após 8 meses de armazenamento, possivelmente devido à degradação dos resíduos tóxicos de glifosate e/ou seus derivados

Lattice QCD Calculation of the Kaon B-parameter with the Wilson Quark Action

The kaon B parameter is calculated in quenched lattice QCD with the Wilson quark action. The mixing problem of the \Delta s=2 four-quark operators is solved non-perturbatively with full use of chiral Ward identities, and this method enables us to construct the weak four-quark operators exhibiting good chiral behavior. We find B_K(NDR, 2GeV)=0.562(64) in the continuum limit, which agrees with the value obtained with the Kogut-Susskind quark action.Comment: 11 pages, latex source-file, 4 figures as ps-fil

Switchable magnetic bulk photovoltaic effect in the two-dimensional magnet CrI3

The bulk photovoltaic effect (BPVE) rectifies light into the dc current in a single-phase material and attracts the interest to design high-efficiency solar cells beyond the pn junction paradigm. Because it is a hot electron effect, the BPVE surpasses the thermodynamic Shockley–Queisser limit to generate above-band-gap photovoltage. While the guiding principle for BPVE materials is to break the crystal centrosymmetry, here we propose a magnetic photogalvanic effect (MPGE) that introduces the magnetism as a key ingredient and induces a giant BPVE. The MPGE emerges from the magnetism-induced asymmetry of the carrier velocity in the band structure. We demonstrate the MPGE in a layered magnetic insulator CrI3, with much larger photoconductivity than any previously reported results. The photocurrent can be reversed and switched by controllable magnetic transitions. Our work paves a pathway to search for magnetic photovoltaic materials and to design switchable devices combining magnetic, electronic, and optical functionalities

Charm quark system at the physical point of 2+1 flavor lattice QCD

We investigate the charm quark system using the relativistic heavy quark action on 2+1 flavor PACS-CS configurations previously generated on $32^3 \times 64$ lattice. The dynamical up-down and strange quark masses are set to the physical values by using the technique of reweighting to shift the quark hopping parameters from the values employed in the configuration generation. At the physical point, the lattice spacing equals $a^{-1}=2.194(10)$ GeV and the spatial extent $L=2.88(1)$ fm. The charm quark mass is determined by the spin-averaged mass of the 1S charmonium state, from which we obtain m_{\rm charm}^{\msbar}(\mu = m_{\rm charm}^{\msbar}) = 1.260(1)(6)(35) GeV, where the errors are due to our statistics, scale determination and renormalization factor. An additional systematic error from the heavy quark is of order $\alpha_s^2 f(m_Q a)(a \Lambda_{QCD})$, which is estimated to be a percent level if the factor $f(m_Q a)$ analytic in $m_Q a$ is of order unity. Our results for the charmed and charmed-strange meson decay constants are $f_D=226(6)(1)(5)$ MeV, $f_{D_s}=257(2)(1)(5)$ MeV, again up to the heavy quark errors of order $\alpha_s^2 f(m_Q a)(a \Lambda_{QCD})$. Combined with the CLEO values for the leptonic decay widths, these values yield $|V_{cd}| = 0.205(6)(1)(5)(9)$, $|V_{cs}| = 1.00(1)(1)(3)(3)$, where the last error is on account of the experimental uncertainty of the decay widths.Comment: 16 pages, 12 figure

An attempt toward the generalized Langevin dynamics simulation

An attempt to generalize the Langevin dynamics simulation method is presented based on the generalized Langevin theory of liquids, in which the dynamics of both solute and solvent is treated by the generalized Langevin equations, but the integration of the equation of motion of solute is made in the manner similar to the ordinary molecular dynamics simulation with discretized time steps along a trajectory. A preliminary result is derived based on an assumption of the uniform solvent density. The result is regarded to be a microscopic generalization of the phenomenological Langevin theory for the harmonic oscillator immersed in a continuum solvent developed by Wang and Uhlenbeck.Представлено спробу узагальнити метод моделювання ланжевенiвської динамiки на основi узагальненої ланжевенiвської теорiї рiдин, в яких динамiка i домiшки i розчинника розглядається узагальненими рiвняннями Ланжевена, але iнтегрування рiвнянь руху домiшки робиться подiбним чином до звичайного методу молекулярної динамiки з дискретизованим часовим кроком вздовж траєкторiї. Отримано попереднiй результат, що грунтується на припущеннi однорiдної густини розчинника. Результат трактується як мiкроскопiчне узагальнення феноменологiчної ланжевенiвської теорiї для гармонiчного осцилятора, помiщеного у суцiльне середовище розчинника, що розроблялась Ванґом та Уленбеком

The Strange Prospects for Astrophysics

The implications of the formation of strange quark matter in neutron stars and in core-collapse supernovae is discussed with special emphasis on the possibility of having a strong first order QCD phase transition at high baryon densities. If strange quark matter is formed in core-collapse supernovae shortly after the bounce, it causes the launch of a second outgoing shock which is energetic enough to lead to a explosion. A signal for the formation of strange quark matter can be read off from the neutrino spectrum, as a second peak in antineutrinos is released when the second shock runs over the neutrinosphere.Comment: 10 pages, 8 figures, invited talk given at the international conference on strangeness in quark matter (SQM2008), Beijing, October 6-10, Beijing, China, version to appear in J. Phys.

Silicon leaf application and physiological quality of white oat and wheat seeds.

Plant nutrition can positively influence quality of seeds by improving plant tolerance to adverse climate. In this context, silicon is currently considered a icronutrient and it is beneficial to plant growth, especially Poaceaes such as white oat and wheat, thereby improving physiological quality of seeds. This study had the objective of evaluating the effects of silicon leaf application on plant tillering, silicon levels and physiological quality of white oat and wheat seeds besides establishing correlations between them. Two experiments were carried out in winter with white oat and wheat. The experimental design was the completely randomized block with eight replications. Treatments consisted of foliar application of silicon (0.8% of soluble silicon, as stabilized orthosilicic acid) and a control (with no application). Silicon levels in leaves were determined at flowering whereas the number of plants and panicles/spikes per area was counted right before harvest. Seed quality was evaluated right after harvest through mass, germination and vigor tests. Data was submitted to variance analysis and means were compared by the Tukey test at a probability level of 5%. Person?s linear correlation test was performed among silicon level in plants, tillering and seed quality data. Silicon leaf application increases root and total length of white oat seedlings as an effect of higher Si level in leaves. Silicon leaf application increases mass of wheat seeds without affecting germination or vigor