279 research outputs found
Quark CP-Phase and Froggatt-Nielsen Mechanism
On the basis of the Froggatt-Nielsen mechanism, we study quark flavor mixings
in the model. The characteristic structure of the CKM
matrix is attributed to the hierarchical effective Yukawa couplings due to the
Froggatt-Nielsen mechanism and also to the state-mixings beyond the MSSM. We
elucidate the detailed form of the CKM matrix elements and find interesting
relations between the \textit{CP} violating phase and three mixing angles.
Taking the existing data of three mixing angles, we estimate the quark
\textit{CP}-phase at . This result is in accord
with observations.Comment: 14 pages, no figure. To be published in Physics Letters B. Several
sentences are added. arXiv admin note: text overlap with arXiv:1210.376
The String Unufication of Gauge Cuoplings and Gauge Kinetic Mixings
In the superstring models we have not only the complete {\bf 27} multiplets
of but also extra incomplete chiral
supermultiplets being alive at low energies. Associated with these additional
multiplets, when the gauge symmetry contains more than one gauge group,
there may exist gauge kinetic mixings among these gauge groups. In such
cases the effect of gauge kinetic mixings should be incorporated into the study
of unification of gauge couplings. We study these interesting effects
systematically in these models. The string threshold effect is also taken into
account. It is found that in the four-generation models we do not have a
advisable solution of string unification of gauge couplings consistent with
experimental values at the electroweak scale. We also discuss the possible
scenarios to solve this problem.Comment: 27 pages, LaTeX, DPNU-93-16, AUE-03-9
The Aligned Model
In Calabi-Yau string compactification, it is pointed out that there exists a
new type of model (the aligned
model) in which the differs from the standard and also from the
flipped . With the aid of the discrete symmetry suggested from Gepner
model, we construct a simple and phenomenologically interesting
three-generation model with the aligned gauge symmetry.
The triplet-doublet splitting problem can be solved. It is also found that
there is a realistic solution for solar neutrino problem and for the -problem. At low energies this model is in accord with the minimal
supersymmetric standard model except for the existence of singlet fields with
masses of TeV.Comment: LaTeX 24 page
Students with dyslexia: research projects at Northumbria University
Northumbria University has about 700 registered disabled students, the majority of whom (around 58 per cent) are registered as having dyslexia and account for approximately two per cent of the total student population. Therefore dyslexic students represent the largest single group of disabled students and are those with whom most staff are likely to come into contact. The research authors were keen to ascertain whether there was a difference in academic performance between dyslexic and non-dyslexic students in respect of degree classification and assignment marks and to investigate whether dyslexic students generally felt supported in their academic studies. Research involved both qualitative and quantitative strands and the areas explored include pre expectations; general support throughout study; methods, flexibility and clarity of learning tasks, in particular assessment and levels of performance throughout and at the end of their study. This research is ongoing, however, findings have proved invaluable as a basis in the construction of good practice guidelines in dealing with the pedagogic needs of this diverse student grou
Long-term oxygen therapy in Japan: history, present status, and current problems
Historically, the progress of long term-oxygen therapy (LTOT) in Japan has been characterized by collaboration among academicgroups, policy makers, and industrial companies. The public health insurance program has covered the cost of LTOT since 1985.Thomas Petty’s group in Denver enthusiastically carried out the public implementation of LTOT and conveyed the concept of pulmonaryrehabilitation for the processing with LTOT. Although the target diseases of LTOT in Japan tended to be chronic obstructivepulmonary disease or sequelae of primary lung tuberculosis, it was soon applied for cardiac diseases as well as other pulmonarydiseases. Together with increasing medical costs for geriatric patients, the political conversion from hospital based care ofa traditional style to home care system has been performed, with two background reasons: the improvement of quality of life ofpatients and the reduction of the medical expense. Presently, LTOT plays a pivotal role in the successful implementation of homerespiratory care for elderly patients. In addition, this promotes comprehensive pulmonary rehabilitation, a team approach, andclose liaisons between primary care and hospitals. Currently, the total number of patients using LTOT exceeds 150,000. In Japan,LTOT resulted in an advancement in the medical care as well as in administrative decision to introduce it as a nationwide systemafter analyzing the results of opinion polls of patients with respiratory failure. However, the recent great earthquake in East Japanrevealed that many unresolved problems remain for these patients, and these issues are of great concern.Historically, the progress of long term-oxygen therapy (LTOT) in Japan has been characterized by collaboration among academicgroups, policy makers, and industrial companies. The public health insurance program has covered the cost of LTOT since 1985.Thomas Petty’s group in Denver enthusiastically carried out the public implementation of LTOT and conveyed the concept of pulmonaryrehabilitation for the processing with LTOT. Although the target diseases of LTOT in Japan tended to be chronic obstructivepulmonary disease or sequelae of primary lung tuberculosis, it was soon applied for cardiac diseases as well as other pulmonarydiseases. Together with increasing medical costs for geriatric patients, the political conversion from hospital based care ofa traditional style to home care system has been performed, with two background reasons: the improvement of quality of life ofpatients and the reduction of the medical expense. Presently, LTOT plays a pivotal role in the successful implementation of homerespiratory care for elderly patients. In addition, this promotes comprehensive pulmonary rehabilitation, a team approach, andclose liaisons between primary care and hospitals. Currently, the total number of patients using LTOT exceeds 150,000. In Japan,LTOT resulted in an advancement in the medical care as well as in administrative decision to introduce it as a nationwide systemafter analyzing the results of opinion polls of patients with respiratory failure. However, the recent great earthquake in East Japanrevealed that many unresolved problems remain for these patients, and these issues are of great concern
Semidirect product gauge group and quantization of hypercharge
In the Standard Model the hypercharges of quarks and leptons are not
determined by the gauge group alone. We show that, if we choose the semidirect product group
as its gauge group,
the hyperchages are settled to be . In
addition, the conditions for gauge-anomaly cancellation give strong
constraints. As a result, the ratios of the hypercharges are uniquely
determined and the gravitational anomaly is automatically canceled. The
standard charge assignment to quarks and leptons can be properly reproduced.
For exotic matter fields their hypercharges are also discussed.Comment: 17 pages, 2 tables; LaTeX; typos corrected, references added or
replaced, argument in Secs. 2 and 3 revised, results unchanged; to be
published in Phys. Rew.
The Weak-Scale Hierarchy and Discrete Symmetries
In the underlying Planck scale theory we introduce a certain type of discrete
symmetry, which potentially brings the stability of the weak-scale hierarchy
under control. Under the discrete symmetry the -problem and the tadpole
problem can be solved simultaneously without relying on some fine-tuning of
parameters. Instead, it is required that doublet Higgs and color-triplet Higgs
fields reside in different irreducible representations of the gauge symmetry
group at the Planck scale and that they have distinct charges of the discrete
symmetry group.Comment: 13 pages, LATEX, 1 figures(not included, available on request by fax
or Postscript file
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