Non-perturbative Renormalization of the Complete Basis of Four-fermion Operators and B-parameters

We present results on the B-parameters $B_K$, $B^{3/2}_7$ and $B^{3/2}_8$, at $\beta=6.0$, with the tree-level Clover action. The renormalization of the complete basis of dimension-six four-fermion operators has been performed non-perturbatively. Our results for $B_K$ and $B^{3/2}_7$ are in reasonable agreement with those obtained with the (unimproved) Wilson action. This is not the case for $B^{3/2}_8$. We also discuss some subtleties arising from a recently proposed modified definition of the B-parameters.Comment: Talk presented at Lattice '97, Edinburgh (UK), July 1997. LaTeX 3 pages, uses espcrc

Lattice B-parameters for ΔS=2\Delta S = 2 and ΔI=3/2\Delta I = 3/2 Operators

We compute several matrix elements of dimension-six four-fermion operators and extract their B-parameters. The calculations have been performed with the tree-level Clover action at $\beta = 6.0$. The renormalization constants and mixing coefficients of the lattice operators have been obtained non-perturbatively. In the \MSbar renormalization scheme, at a renormalization scale $\mu \simeq 2$ GeV, we find $B_K (B_9^{3/2}) = 0.66(11), B_7^{3/2} = 0.72(5)$ and $B_8^{3/2} = 1.03(3)$. The result for $B_8^{3/2}$ has important implications for the calculation of $\epsilon^\prime / \epsilon$.Comment: LaTeX, 14 pages, revised version (sign misprint in eq. (21) corrected

Delta M_K and epsilon_K in SUSY at the Next-to-Leading order

We perform a Next-to-Leading order analysis of Delta S=2 processes beyond the Standard Model. Combining the recently computed NLO anomalous dimensions and the B parameters of the most general Delta S=2 effective Hamiltonian, we give an analytic formula for Delta M_K and epsilon_K in terms of the Wilson coefficients at the high energy scale. This expression can be used for any extension of the Standard Model with new heavy particles. Using this result, we consider gluino-mediated contributions to Delta S=2 transitions in general SUSY models and provide an improved analysis of the constraints on off-diagonal mass terms between the first two generations of down-type squarks. Finally, we improve the constraints on R-violating couplings from Delta M_K and epsilon_K.Comment: 20 pages, 1 figure, uses JHEP.cls; the magic numbers in eq. (2.7), previously given in the basis (13) of hep-ph/9711402, are now given in the basis (2.3) of this work. All numerical results are unchange

Mixing of B mesons and Decay Constants with the Non-Perturbatively Improved Action

Several quantities relevant to phenomenological studies of the mixing of neutral B mesons are computed on the lattice. Our main results are: f_{Bd} sqrt(B_{Bd})=206(28)(7) MeV, f_{Bs} sqrt(B_{Bs})/f_{Bd}sqrt(B_{Bd})=1.16(7). We also obtain the related quantities f_{Bs}sqrt(B{Bs})=237(18)(8) MeV, f_{Bd}= 174(22)(+7-0)(-4-0) MeV, f_{Bs}= 204(15)(+7-0)(+3-0) MeV, f_{Bs}/f_{Bd}=1.17(4)(+0-1), f_{Bd}/f_{Ds}=0.74(5). After combining our results with the experimental world average (Delta m_d), we predict (Delta m_s)=15.8(2.1)(3.3) ps^{-1}. We have also computed the relevant parameters for mixing of neutral D mesons which may be useful in some extensions of the Standard Model. All the quantities were obtained from a quenched simulation with a non-perturbatively improved Clover action at beta=6.2, corresponding to a lattice spacing 1/a=2.7(1) GeV, on a sample of 200 gauge-field configurations. A discussion of the main systematic errors is also presented.Comment: 21 pages (LaTeX2e), 5 PostScript figure

B-parameters for DeltaS = 2 Supersymmetric Operators

We present a calculation of the matrix elements of the most general set of DeltaS=2 dimension-six four-fermion operators. The values of the matrix elements are given in terms of the corresponding B-parameters. Our results can be used in many phenomenological applications, since the operators considered here give important contributions to K^0--K^0bar mixing in several extensions of the Standard Model (supersymmetry, left-right symmetric models, multi-Higgs models etc.). The determination of the matrix elements improves the accuracy of the phenomenological analyses intended to put bounds on basic parameters of the different models, as for example the pattern of the sfermion mass matrices. The calculation has been performed on the lattice, using the tree-level improved Clover action at two different values of the strong coupling constant (beta=6/g_0^2(a)=6.0 and 6.2, corresponding to a^-1= 2.1 and 2.7 GeV respectively), in the quenched approximation. The renormalization constants and mixing coefficients of the lattice operators have been obtained non-perturbatively.Comment: Comparison with results of ref.[22] added in sect. 4; updated ref.[7

Validación del gen de resistencia a “escaldadura” Rrs2 en los cultivares de cebada cervecera con mayor difusión en Argentina

La “escaldadura” es una enfermedad importante en el cultivo de cebada. En la literatura se han descripto genes que confieren resistencia genética (Rrs) a esta enfermedad. En Argentina, más del 80% del área sembrada de cebada corresponde a las variedades Shakira, Andreia y Scarlett. La primera porta alelos de resistencia para el gen Rrs2, los cuales pueden ser identificados por técnicas moleculares. Sin embargo, no existen reportes de la respuesta fenotípica de estos cultivares en zonas de producción agrícola de cebada en Argentina. El objetivo de este trabajo fue validar el gen Rrs2, involucrado en la resistencia para “escaldadura” en las variedades de cebada más difundidas en Argentina y determinar si el marcador desarrollado sobre dicho gen puede ser aplicado en selección asistida en programas de mejoramiento. Para ello, se utilizaron los cultivares Scarlett, Andreia y Shakira y una población biparental RIL de 158 individuos derivada del cruzamiento de Andreia y Shakira. Los genotipos fueron caracterizados fenotípicamente a campo en las localidades de Bordenave, Balcarce y Coronel Suárez. Además, se caracterizaron molecularmente por la presencia (Rrs2+) o ausencia (Rrs2-) de alelos de resistencia. Los resultados muestran que los genotipos parentales Shakira y Andreia presentan respuestas altamente contrastantes en los tres ambientes de evaluación. Las líneas derivadas de este cruzamiento mostraron diversas respuestas frente al patógeno. Se observó que no existen diferencias significativas entre las líneas que portan el alelo de resistencia (Rrs2+) y la variedad Shakira. Tampoco se encontraron diferencias significativas al analizar la respuesta de las líneas que portan el alelo de susceptibilidad (Rrs2-) y la variedad Andreia. Sin embargo, ambos grupos de líneas difieren significativamente entre sí, de la misma manera que lo hacen las variedades usadas como parentales. Tanto la variedad Shakira como las líneas portadoras de Rrs2+ presentaron buena respuesta frente a la enfermedad. Esto indica que dicho alelo sería el responsable de la resistencia frente al patógeno para estos genotipos. En contraste, la variedad Andreia y las líneas Rrs2- mostraron alta presencia de síntomas de la enfermedad, lo cual confirma que estos genotipos carecen de genes de resistencia efectivos para dicha enfermedad. Además, el marcador molecular desarrollado sobre el gen Rrs2 mostró ser eficaz en la selección de líneas derivadas del cruzamiento entre ambos cultivares. Esto indica que dicho marcador podría ser utilizado en planes de mejoramiento que utilicen fondos genéticos derivados de la variedad Shakira para la selección de individuos que porten alelos de resistencia a la enfermedad. Por último, este trabajo representa la primera caracterización a nivel fenotípico y molecular de cultivares de cebada cervecera utilizados ampliamente en sistemas de producción agrícola en las principales zonas agroecológicas de Argentina.“Scald” is an important disease in barley cultivation. In the literature, genes responsible for resistance (Rrs) have been described, which are present in barley cultivars. In Argentina, more than 70% of the area planted with barley corresponds to the Shakira and Andreia varieties. Shakira carries resistance alleles for the Rrs2 gene which can be identified by molecular techniques; however there are no reports of the response of these materials in agricultural production areas of barley in Argentina. The objective of this work was to validate the Rrs2 gene as a carrier of resistance alleles for “scald” in the most widespread varieties of barley in Argentina and to determine if the molecular marker developed on said gene can be applied in assisted selection in breeding programs. For this purpose, we used a biparental population RIL of 158 individuals derived from Andreia and Shakira. The materials were phenotypically characterized to field in the localities of Bordenave, Balcarce and Coronel Suárez. In addition, they were characterized molecularly by the presence (Rrs2 +) or absence (Rrs2-) of resistance alleles. The results show that the parents Shakira and Andreia present highly contrasting responses in the three evaluation environments. The lines showed different responses to the pathogen, it was observed that there are no significant differences between the lines carrying the resistance allele (Rrs2 +) and the Shakira variety, not were significant differences found when analyzing the response of the lines carrying the allele susceptibility (Rrs2-) and the variety Andreia. However, both groups of lines differ significantly from each other, in the same way that the varieties used as parental do. Both, the Shakira variety and the Rrs2 + lines showed good response to the disease, indicating that the allele would be responsible for the resistance to the pathogen for these materials. In contrast, Andreia and Rrs2- lines showed high presence of symptoms, indicating that these materials lack effective resistance genes for this disease. In addition, the molecular marker developed on the Rrs2 gene was shown to be effective in selecting lines derived from the crossing of both materials, indicating that this marker could be used in breeding programs that use genetic backgrounds derived from the Andreia and Shakira varieties for the selection of individuals carrying alleles of resistance to the disease. Finally, this work represents the first phenotypic and molecular approximation of brewing barley materials widely used in agricultural production systems in the main agroecological zones of Argentina.EEA BordenaveFil: Gonzalez, Germán Andrés. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Bordenave; ArgentinaFil: Moreyra, Federico. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Bordenave; ArgentinaFil: Conti, Veronica Andrea. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Bordenave; ArgentinaFil: Vallati, Alejandro Rodolfo. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Bordenave; ArgentinaFil: Gimenez, Fernando Jose. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Bordenave; Argentin

Animal Models of Cancer in the Head and Neck Region

Animal models that resemble the cancers of the head and neck region are of paramount importance in studying the carcinogenesis of these diseases. Although several methods for modeling cancer in the head and neck are available, none are fully satisfactory. Subcutaneous xenograft models of cancer in nude mice are often used in preclinical studies. However, these models are problematic in several aspects as they lack the specific interactions that exist between the tumor cells and their native environment. Establishment of tumors at the orthotopic sites restore these distinct patterns of interactions between the tumor and the host organs that are lost or altered when the tumors are established in ectopic sites. With regard to the transgenic model of cancer in the head and neck region, it should be kept in mind that the transgene used to drive the malignant transformation may not be representative of the carcinogenic process found in human tumors. Low penetrance of tumor formation also translates into high cost and time commitment in performing studies with transgenic models. In this review, we will discuss some of the commonly used methods for modeling cancer in the head and neck region including squamous cell carcinoma of the head and neck as well as thyroid carcinoma

Observation of associated near-side and away-side long-range correlations in √sNN=5.02 TeV proton-lead collisions with the ATLAS detector

Two-particle correlations in relative azimuthal angle (Δϕ) and pseudorapidity (Δη) are measured in √sNN=5.02  TeV p+Pb collisions using the ATLAS detector at the LHC. The measurements are performed using approximately 1  μb-1 of data as a function of transverse momentum (pT) and the transverse energy (ΣETPb) summed over 3.1<η<4.9 in the direction of the Pb beam. The correlation function, constructed from charged particles, exhibits a long-range (2<|Δη|<5) “near-side” (Δϕ∼0) correlation that grows rapidly with increasing ΣETPb. A long-range “away-side” (Δϕ∼π) correlation, obtained by subtracting the expected contributions from recoiling dijets and other sources estimated using events with small ΣETPb, is found to match the near-side correlation in magnitude, shape (in Δη and Δϕ) and ΣETPb dependence. The resultant Δϕ correlation is approximately symmetric about π/2, and is consistent with a dominant cos⁡2Δϕ modulation for all ΣETPb ranges and particle pT

Search for direct production of charginos and neutralinos in events with three leptons and missing transverse momentum in √s = 7 TeV pp collisions with the ATLAS detector

A search for the direct production of charginos and neutralinos in final states with three electrons or muons and missing transverse momentum is presented. The analysis is based on 4.7 fb−1 of proton–proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in three signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric models and in simplified models, significantly extending previous results

Measurement of χ c1 and χ c2 production with s√ = 7 TeV pp collisions at ATLAS

The prompt and non-prompt production cross-sections for the χ c1 and χ c2 charmonium states are measured in pp collisions at s√ = 7 TeV with the ATLAS detector at the LHC using 4.5 fb−1 of integrated luminosity. The χ c states are reconstructed through the radiative decay χ c → J/ψγ (with J/ψ → μ + μ −) where photons are reconstructed from γ → e + e − conversions. The production rate of the χ c2 state relative to the χ c1 state is measured for prompt and non-prompt χ c as a function of J/ψ transverse momentum. The prompt χ c cross-sections are combined with existing measurements of prompt J/ψ production to derive the fraction of prompt J/ψ produced in feed-down from χ c decays. The fractions of χ c1 and χ c2 produced in b-hadron decays are also measured