4,114 research outputs found
Spontaneous CP Violation in a SUSY Model with a complex CKM
It is pointed out that the recent measurement of the angle of the
unitarity triangle, providing irrefutable evidence for a complex
Cabibbo-Kobayashi-Maskawa (CKM) matrix, presents a great challenge for
supersymmetric models with spontaneous CP violation. We construct a new minimal
extension of the minimal supersymmetric standard model (MSSM), with spontaneous
CP breaking, which leads to a complex CKM matrix, thus conforming to present
experimental data. This is achieved through the introduction of two singlet
chiral superfields and a vector-like quark chiral superfield which mixes with
the standard quarks. A symmetry is introduced in order to have a
potential solution to the strong CP problem.Comment: 12 pages. Uses the elsart.cls LaTeX class. Minor corrections and
references adde
Nearest-Neighbour Interaction from an Abelian Symmetry and Deviations from Hermiticity
We show that Nearest-Neighbour Interaction (NNI) textures for the quark mass
matrices can be obtained through the introduction of an Abelian flavour
symmetry. The minimal realisation requires a Z_4 symmetry in the context of a
two Higgs doublet model. It is further shown that the NNI textures can be in
agreement with all present experimental data on quark masses and mixings,
provided one allows for deviations of Hermiticity in the quark mass matrices at
the 20% level.Comment: 11 pages, 1 figure; references and minor corrections adde
Texture Zeros and Weak Basis Transformations
We investigate the physical meaning of some of the "texture zeros" which
appear in most of the Ansatze on quark masses and mixings. It is shown that
starting from arbitrary quark mass matrices and making a suitable weak basis
transformation one can obtain some of these sets of zeros which therefore have
no physical content. We then analyse the physical implications of a
four-texture zero Ansatz which is in agreement with all present experimental
data.Comment: 11 pages, typeset using revte
The role of traditional land use systems in the well-being of rural Timor-Leste
Natural ecosystems and traditional land use systems have an important role in the life and well being of the rural population of Timor-Leste. The land itself is the support of natural ecosystems and subsistence agriculture of rural populations of East Timor and is the main focus of this research. This paper is part of work in progress. Our research, located in rural Timor-Leste focuses on land tenure, rural family income and the mechanisms that will induce changes in the rules of traditional society organisation. The main objectives of this paper are: 1) to identify the different land use patterns of Timor-Leste; 2) to identify the goods and services produced by them and 3) to relate the services produced by land use patterns with the well-being of Timor-Leste rural population. This paper is based on a multidisciplinary approach incorporating contributions from several fields of knowledge, and uses documentary sources, direct observations made in various periods in the field and interviews conducted in 2003, 2009 and 2010. We identify as the main land use patterns in Timor-Leste the following ones: natural and semi-natural ecosystems, subsistence agriculture, sacred, housing and basic infrastructures and Industries and services. For Timor-Leste rural communities the above land use patterns produce a set of goods and services, which can be classified as supporting, provisioning, regulating and cultural goods and services, and those are essential for their survival and well-being. The conceptual framework used to examine the above mentioned issues is the human rights approach to development within which human rights are considered as means and objectives of development as much as economic purposes.Timor-Leste, land use patterns, ecosystems goods and services, well-being.
Dynamical CP Violation and Flavour-Changing Processes
We investigate the phenomenological constraints on a model where, besides the
standard model Higgs sector, there is an effective new strong interaction
acting on the third generation of quarks and characterized by a -like
term. This term induces electroweak symmetry breaking and leads to
dynamical spontaneous CP violation. We show that the constraints coming from K
physics and the electric dipole moment of the neutron impose that the new
physics scale should be of the order of 35 TeV. Contrary to naive expectations,
the predictions of the model for B physics are very close to the standard model
ones. The main differences appear in processes involving the up quarks such as
mixing and in the electric dipole moment of the neutron, which
should be close to the experimental limit. Possible deviations from the
standard model predictions for CP asymmetries in B decays are also considered.Comment: LaTeX, 25 pages, 4 figure
Jarlskog-like invariants for theories with scalars and fermions
Within the framework of theories where both scalars and fermions are present,
we develop a systematic prescription for the construction of CP-violating
quantities that are invariant under basis transformations of those matter
fields. In theories with Spontaneous Symmetry Breaking, the analysis involves
the vevs' transformation properties under a scalar basis change, with a
considerable simplification of the study of CP violation in the scalar sector.
These techniques are then applied in detail to the two Higgs-doublet model with
quarks. It is shown that there are new invariants involving scalar-fermion
interactions, besides those already derived in previous analyses for the
fermion-gauge and scalar-gauge sectors.Comment: 12 pages, Latex, no figure
Hypoglycemia in a Dog
On December 15, 1958, an eight and one half year old male German Shepherd entered the I.S.U. Veterinary Clinic for examination with a history of incoordination and convulsions. Since about September 15, 1958, the dog had several convulsions, the last of which was rather violent and accompanied by a temperature of 104° F. He had appeared normal and in good condition on November 3, when examined by another veterinarian except for a peculiar crossing over gait and an occasional collapse of the rear quarters. At times the front legs seemed to be involved. The dog had been kept on KjD (Hill Packing Co.) because of a mild chronic nephritis. But on December 15, the Shepherd had deteriorated markedly and had lost a lot of condition. although the appetite was reported to be good. The motor control of the hind legs was very poor. Motion being extren1ely difficult, he fell over or went down behind quite often
Yukawa Structure with Maximal Predictability
A simple Ansatz for the quark mass matrices is considered, based on the
assumption of a power structure for the matrix elements and the requirement of
maximal predictability. A good fit to the present experimental data is obtained
and the position of the vertex of the unitarity triangle, i.e.
(\bar{\rho},\bar{\eta}), is predicted.Comment: 13 pages, 2 EPS figures, some modifications and references added;
version to appear in Phys. Lett.
A Complex Case of Cholestasis in a Patient with ABCB4 and ABCB11 Mutations
The low-phospholipid-associated cholelithiasis (LPAC) syndrome is a form of symptomatic cholelithiasis occurring in young adults, characterized by recurrence of symptoms after cholecystectomy and presence of hepatolithiasis. The case refers to a healthy 39-year-old Caucasian male who presented with abdominal pain and jaundice. His blood tests showed conjugated hyperbilirubinemia and elevated liver enzymes (total bilirubin 6.65 mg/dL, Îł-glutamyltransferase 699 IU/L) and abdominal computed tomography revealed dilation of common bile duct and left intrahepatic ducts. Magnetic resonance cholangiopancreatography identified choledocholithiasis, retrieved by endoscopic retrograde cholangiopancreatography, after which there was a worsening of jaundice (total bilirubin 23 mg/dL), which persisted for several weeks, possibly due to ciprofloxacin toxicity. After an extensive workup including liver biopsy, the identification of two foci of hepatolithiasis on reevaluation abdominal ultrasound raised the hypothesis of LPAC syndrome and the patient was started on ursodeoxycholic acid, with remarkable improvement. Genetic testing identified the mutation c.1954A>G (p.Arg652Gly) in ABCB4 gene (homozygous) and c.1331T>C (p.Val444Ala) in ABCB11 gene (heterozygous). In conclusion, we describe the unique case of an adult male with choledocholithiasis, hepatolithiasis, and persistent conjugated hyperbilirubinemia after retrieval of stones, fulfilling the criteria for LPAC syndrome and with possible superimposed drug-induced liver injury, in whom ABCB4 and ABCB11 mutations were found, both of which had not been previously described in association with LPAC.info:eu-repo/semantics/publishedVersio
Large effects on \BsBs mixing by vector-like quarks
We calculate the contributions of the vector-like quark model to \BsBs
mixing, taking into account the constraints from the decay . In
this model the neutral bosons mediate flavor-changing interactions at the tree
level. However, \BsBs mixing is dominated by contributions from the box
diagrams with the top quark and the extra up-type quark. In sizable ranges of
the model parameters, the mixing parameter is much different from the
standard model prediction.Comment: 11 pages, 4 figures, To be published in Phys. Rev.
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