TeV Symmetry and the Little Hierarchy Problem

Constraints from precision electroweak measurements reveal no evidence for new physics up to 5 - 7 TeV, whereas naturalness requires new particles at around 1 TeV to address the stability of the electroweak scale. We show that this "little hierarchy problem" can be cured by introducing a symmetry for new particles at the TeV scale. As an example, we construct a little Higgs model with this new symmetry, dubbed T-parity, which naturally solves the little hierarchy problem and, at the same time, stabilize the electroweak scale up to 10 TeV. The model has many important phenomenological consequences, including consistency with the precision data without any fine-tuning, a stable weakly-interacting particle as the dark matter candidate, as well as collider signals completely different from existing little Higgs models, but rather similar to the supersymmetric theories with conserved R-parity.Comment: 15 pages, 1 figure; v.2: typos corrected and various minor modifications/expansions on the presentations. now 16 pages and 1 figure. version to appear on JHE

CDMS, Supersymmetry and Extra Dimensions

The CDMS experiment aims to directly detect massive, cold dark matter particles originating from the Milky Way halo. Charge and lattice excitations are detected after a particle scatters in a Ge or Si crystal kept at ~30 mK, allowing to separate nuclear recoils from the dominating electromagnetic background. The operation of 12 detectors in the Soudan mine for 75 live days in 2004 delivered no evidence for a signal, yielding stringent limits on dark matter candidates from supersymmetry and universal extra dimensions. Thirty Ge and Si detectors are presently installed in the Soudan cryostat, and operating at base temperature. The run scheduled to start in 2006 is expected to yield a one order of magnitude increase in dark matter sensitivity.Comment: To be published in the proceedings of the 7th UCLA symposium on sources and detection of dark matter and dark energy in the universe, Marina del Rey, Feb 22-24, 200

Collider aspects of flavour physics at high Q

This review presents flavour related issues in the production and decays of heavy states at LHC, both from the experimental side and from the theoretical side. We review top quark physics and discuss flavour aspects of several extensions of the Standard Model, such as supersymmetry, little Higgs model or models with extra dimensions. This includes discovery aspects as well as measurement of several properties of these heavy states. We also present public available computational tools related to this topic.Comment: Report of Working Group 1 of the CERN Workshop ``Flavour in the era of the LHC'', Geneva, Switzerland, November 2005 -- March 200

Estimating across-trial variability parameters of the Diffusion Decision Model: Expert advice and recommendations

For many years the Diffusion Decision Model (DDM) has successfully accounted for behavioral data from a wide range of domains. Important contributors to the DDM’s success are the across-trial variability parameters, which allow the model to account for the various shapes of response time distributions encountered in practice. However, several researchers have pointed out that estimating the variability parameters can be a challenging task. Moreover, the numerous fitting methods for the DDM each come with their own associated problems and solutions. This often leaves users in a difficult position. In this collaborative project we invited researchers from the DDM community to apply their various fitting methods to simulated data and provide advice and expert guidance on estimating the DDM’s across-trial variability parameters using these methods. Our study establishes a comprehensive reference resource and describes methods that can help to overcome the challenges associated with estimating the DDM’s across-trial variability parameters

Relações entre a concentração de íons e a salinidade de águas subterrâneas e superficiais, visando à irrigação, no sertão de Pernambuco Relationship between ions concentration and salinity of subsurface and surface waters for irrigation in the semi-arid region of Pernambuco State, Brazil

Objetivando-se verificar as relações entre a condutividade elétrica de águas subterrâneas e superficiais (CEa, em dS m-1 a 25ºC) e a concentração dos íons: Na+, Ca++ Mg2+ e Cl-, em mmol c L-1, procedeu-se à análise de regressão desses parâmetros em 175 amostras, sendo 75 de águas subterrâneas e 100 de águas superficiais, em 33 municípios do Sertão de Pernambuco. Os resultados evidenciam que os elementos: Na+, Ca2+ + Mg2+ e Cl-, podem ser estimados com bastante confiabilidade, através de equações do tipo: Y= a + bx, conforme discriminação a seguir: a) águas subterrâneas; (Na+) = - 0,710 + 4,765(CEa), R² = 0,91; (Ca2+ + Mg2+) = 0,287 + 4,673(CEa), R² = 0,83; (Cl-) = - 0,569 + 6,152(CEa), R²= 0,93 e b) águas superficiais; (Na+) = - 0,666 + 5,072(CEa), R² = 0,94; (Ca2+ + Mg2+) = 0,978 + 3,223(CEa), R² = 0,78; (Cl-) = - 0,874 + 6,890(CEa), R² = 0,94.<br>The objective of the study was to determine the relationship between the electrical conductivity of subsurface and surface water (ECw in dS/m at 25ºC) and the ion concentration of Na+, Ca2+ + Mg2+ and C1- (in mmol c L-1). The study was based on 75 and 100 samples collected from subsurface and surface waters, respectively, in 33 counties in the semi-arid region of the Pernambuco State. Results showed that elements Na+, Ca2+ + Mg2+ and C1- may be estimated by a single linear regression of the type, Y = a + bx, as described below: a) subsurface water; (Na+) = - 0.710 + 4.765(ECw), R² = 0.91; (Ca2+ + Mg2+) = 0.287 + 4.673 (ECw), R² = 0.83; (C1-) = - 0.569 + 6.152 (ECw), R² = 0.93 and b) surface water; (Na+) = - 0.666 + 5.072 (ECw), R² = 0.94; (Ca2+ + Mg2+) = 0.978 + 3.223 (ECw), R² = 0 78; (C1-) = - 0.874 + 6.890 (ECw), R²= 0.94