12 research outputs found
Leptogenesis and Neutrino Oscillations Within A Predictive G(224)/SO(10)-Framework
A framework based on an effective symmetry that is either G(224)= SU(2)_L x
SU(2)_R xSU(4)^c or SO(10) has been proposed (a few years ago) that
successfully describes the masses and mixings of all fermions including
neutrinos, with seven predictions, in good accord with the data. Baryogenesis
via leptogenesis is considered within this framework by allowing for natural
phases (~ 1/20-1/2) in the entries of the Dirac and Majorana mass-matrices. It
is shown that the framework leads quite naturally, for both thermal as well as
non-thermal leptogenesis, to the desired magnitude for the baryon asymmetry.
This result is obtained in full accord with the observed features of the
atmospheric and solar neutrino oscillations, as well as with those of the quark
and charged lepton masses and mixings, and the gravitino-constraint. Hereby one
obtains a unified description of fermion masses, neutrino oscillations and
baryogenesis (via leptogenesis) within a single predictive framework.Comment: Efficiency factor updated, some clarifications and new references
added. 19 page
PYTHIA 6.4 Physics and Manual
The PYTHIA program can be used to generate high-energy-physics `events', i.e.
sets of outgoing particles produced in the interactions between two incoming
particles. The objective is to provide as accurate as possible a representation
of event properties in a wide range of reactions, within and beyond the
Standard Model, with emphasis on those where strong interactions play a role,
directly or indirectly, and therefore multihadronic final states are produced.
The physics is then not understood well enough to give an exact description;
instead the program has to be based on a combination of analytical results and
various QCD-based models. This physics input is summarized here, for areas such
as hard subprocesses, initial- and final-state parton showers, underlying
events and beam remnants, fragmentation and decays, and much more. Furthermore,
extensive information is provided on all program elements: subroutines and
functions, switches and parameters, and particle and process data. This should
allow the user to tailor the generation task to the topics of interest.Comment: 576 pages, no figures, uses JHEP3.cls. The code and further
information may be found on the PYTHIA web page:
http://www.thep.lu.se/~torbjorn/Pythia.html Changes in version 2: Mistakenly
deleted section heading for "Physics Processes" reinserted, affecting section
numbering. Minor updates to take into account referee comments and new colour
reconnection option
Effect of total androgen ablation on pathologic stage and resection limit status of prostate cancer. Initial results of the Italian PROSIT study.
The likelihood of finding organ-confined untreated prostate cancer (PCa) by pathological examination at the time of radical prostatectomy (RP) is only 50% in patients with clinically organ-confined disease. In addition, tumour is present at the resection margin in approximately 30% of clinical T2 (clinical stage B) cases. The issue of clinical "understaging" and of resection limit positivity have led to the development of novel management practices, including "neoadjuvant" hormonal therapy (NHT). The optimal duration of NHT is unknown. We undertook the present analysis to evaluate the effect of NHT on pathologic stage of PCa and resection limit status in patients with prostate cancer and treated with total androgen ablation either for three or six months before RP. Between January 1996 and February 1998, 259 men with prostate cancer underwent radical retropubic prostatectomy and bilateral pelvic node dissection in the 26 centres participating in the Italian randomised prospective PROSIT study. Whole mount sectioning of the complete RP specimens was adopted in each centre for accurately evaluating the pathologic stage and resection limit status. By February 1998, haematoxylin and eosin stained sections from 155 RP specimens had been received and evaluated by the reviewing pathologist (RM). 64 cases had not been treated with total androgen ablation (e.g. NHT) before RP was performed, whereas 58 and 33 had been treated for three and six months, respectively. 114 patients were clinical stage B whereas 41 were clinical stage C. After three months of total androgen ablation, pathological stage B was more prevalent among patients with clinical B tumours, compared with untreated patients (57% in treated patients vs. 36% in untreated). The percentage of cancers with negative margins was statistically significantly greater in patients treated with neoadjuvant therapy than those treated with immediate surgery alone (69% vs. 42%, respectively). After six months of NHT therapy the proportion of patients with pathological stage B (67% vs. 36%, respectively) and negative margins was greater than after 3 months (92% vs. 42%, respectively). For clinical C tumours, the prevalence of pathological stage B and negative margins in the patients treated for either 3 or 6 months was not as high as in the clinical B tumours, when compared with the untreated group (pathological stage B: 31% and 33% vs. 6% in the clinical C cases, respectively. Negative margins: 56% and 67% vs. 31%, respectively). The initial results of this study suggest that total androgen ablation before RP is beneficial in men with clinical stage B because of the significant pathological downstaging and decrease in the number of positive margins in the RP specimens. These two effects are more pronounced after six months of NHT than after three months of therapy. The same degree of beneficial effects are not observed in clinical C tumours
Search for contact interactions in deep inelastic e(+)p → e(+)X scattering at HERA
In a search for signatures of physics processes beyond the Standard Model, various eeqq vector contact-interaction hypotheses have been tested using the high-Q(2) deep inelastic neutral-current e(+)p scattering data collected with the ZEUS detector at HERA. The data correspond to an integrated luminosity of 47.7pb(-1) of e(+)p interactions at 300 GeV center-of-mass energy. No significant evidence of a contact- interaction signal has been found. Limits at the 95% confidence level are set on the contact-interaction amplitudes. The effective mass scales Lambda corresponding to these limits range from 1.7 TeV to 5 TeV for the contact-interaction scenarios considere