2,654 research outputs found
Heavy Quarkonia sector in PYTHIA 6.324: tuning, validation and perspectives at LHC(b)
In this note we investigate the impact of the recent insertion of Color Octet Model processes in PYTHIA version 6.324, through a tuning of different PYTHIA parameters, including the low-p behaviour. The Non-relativistic QCD parameters have been chosen according to the most recent theoretical calculations and fits to CDF data. This analysis has been mainly focused on J/ and prompt production, with a comparison of the Monte Carlo predictions with available data from CDF at Run I and Run II energies. A prediction at the LHC energy, within different acceptance regions (CMS-Atlas and LHCb ones), is also given
The FIT-pull Method: an experimental tool to monitor the track measurements and the B proper time.
In this note we describe a statistical tool, the \textit{FIT-pull method}, that can test the reliability of the measurements of the tracks and the vertices on real and Monte-Carlo data without knowledge of the truth information. The basic mathematical formalism is derived from the Lagrange Multipliers method and briefly described. Several tests are performed to prove its validity in different situations. %KDifferent useful examples are discussed. In particular, by using Monte-Carlo simulation, we demonstrate that the method can be applied to check if the measured tracks or vertices have biases or incorrect covariance matrices. For correct input measurements we obtain pull distributions with a normal Gaussian statistical form. In this case the B proper time value and its error, which is a function of the track and vertex measurements, are correctly calculated. However, in the case of incorrect measurements, for example due to a systematic error or to a scale factor of the covariance matrix, the pull distributions studied deviate from normal Gaussians and the B proper time measurement can be affected. In principle the method can, if necessary, be used to recover information from corrupted measurements. Its potential in this capacity is demonstrated for the particular case of the decay channel with the reconstructed Monte-Carlo data produced in 2004
Constraints on new physics from the quark mixing unitarity triangle
The status of the Unitarity Triangle beyond the Standard Model including the
most recent results on Delta m_s, on dilepton asymmetries and on width
differences is presented. Even allowing for general New Physics loop
contributions the Unitarity Triangle must be very close to the Standard Model
result. With the new measurements from the Tevatron, we obtain for the first
time a significant constraint on New Physics in the B_s sector. We present the
allowed ranges of New Physics contributions to Delta F=2 processes, and of the
time-dependent CP asymmetry in B_s to J/Psi phi decays.Comment: 5 pages, 4 figures. v2: numerical error in Delta Gamma_s/Gamma_s
corrected. Plots and tables updated. v3: update after ICHEP06, final version
published in Phys Rev Letter
Improved Determination of the CKM Angle alpha from B to pi pi decays
Motivated by a recent paper that compares the results of the analysis of the
CKM angle alpha in the frequentist and in the Bayesian approaches, we have
reconsidered the information on the hadronic amplitudes, which helps
constraining the value of alpha in the Standard Model. We find that the
Bayesian method gives consistent results irrespective of the parametrisation of
the hadronic amplitudes and that the results of the frequentist and Bayesian
approaches are equivalent when comparing meaningful probability ranges or
confidence levels. We also find that from B to pi pi decays alone the 95%
probability region for alpha is the interval [80^o,170^o], well consistent with
recent analyses of the unitarity triangle where, by using all the available
experimental and theoretical information, one gets alpha = (93 +- 4)^o. Last
but not least, by using simple arguments on the hadronic matrix elements, we
show that the unphysical region alpha ~ 0, present in several experimental
analyses, can be eliminated.Comment: 16 pages, 7 figure
Update of the Unitarity Triangle Analysis
We present the status of the Unitarity Triangle Analysis (UTA), within the
Standard Model (SM) and beyond, with experimental and theoretical inputs
updated for the ICHEP 2010 conference. Within the SM, we find that the general
consistency among all the constraints leaves space only to some tension
(between the UTA prediction and the experimental measurement) in BR(B -> tau
nu), sin(2 beta) and epsilon_K. In the UTA beyond the SM, we allow for New
Physics (NP) effects in (Delta F)=2 processes. The hint of NP at the 2.9 sigma
level in the B_s-\bar B_s mixing turns out to be confirmed by the present
update, which includes the new D0 result on the dimuon charge asymmetry but not
the new CDF measurement of phi_s, being the likelihood not yet released.Comment: 4 pages, 2 figures, Proceedings of the 35th International Conference
of High Energy Physics - ICHEP2010 (July 22-28, 2010, Paris
First evidence of new physics in b â s transitions
We combine all the available experimental information on Bs mixing, including the very
recent tagged analyses of Bs â J/ÎšÏ by the CDF and DĂ collaborations. We find that the
phase of the Bs mixing amplitude deviates more than 3Ï from the Standard Model
prediction. While no single measurement has a 3Ï significance yet, all the constraints show
a remarkable agreement with the combined result. This is a first evidence of physics
beyond the Standard Model. This result disfavours New Physics models with Minimal
Flavour Violation with the same significance
New Physics from Flavour
The UT{\it{fit}} Collaboration has produced several analyses in the context
of flavour physics both within and beyond the Standard Model. In this paper we
present updated results for the Standard Model analysis of the Unitarity
Triangle using the latest experimental and lattice QCD inputs, as well as an
update of the Unitarity Triangle analysis in a scenario beyond the Standard
Model. Combining all available experimental and theoretical information on
processes and using a model-independent parameterization, we
extract the allowed New Physics contributions in the , , , and
sectors. We observe a departure of the mixing phase from the
Standard Model expectation with a significance of about .Comment: Heavy Quarks and Leptons, Melbourne, 200
Radiation therapy for atypical and anaplastic meningiomas: an overview of current results and controversial issues
Meningiomas are the most common intracranial tumors. Most meningiomas are WHO grade 1 tumors whereas less than one-quarter of all meningiomas are classified as atypical (WHO grade 2) and anaplastic (WHO grade 3) tumors, based on local invasiveness and cellular features of atypia. Surgical resection remains the cornerstone of meningioma therapy and represents the definitive treatment for the majority of patients; however, grade 2 and grade 3 meningiomas display more aggressive behavior and are difficult to treat. Several retrospective series have shown the efficacy and safety of postoperative adjuvant external beam radiation therapy (RT) for patients with atypical and anaplastic meningiomas. More recently, two phase II prospective trials by the Radiation Therapy Oncology Group (RTOG 0539) and the European Organisation for Research and Treatment of Cancer (EORTC 2042) have confirmed the potential benefits of fractionated RT for patients with intermediate and high-risk meningiomas; however, several issues remain a matter of debate. Controversial topics include the timing of radiation treatment in patients with totally resected atypical meningiomas, the optimal radiation technique, dose and fractionation, and treatment planning/target delineation. Ongoing randomized trials are evaluating the efficacy of early adjuvant RT over observation in patients undergoing gross total resection. © 2022, The Author(s
Standard Model updates and new physics analysis with the Unitarity Triangle ïŹt
International audienceWe present the update of the Unitarity Triangle (UT) analysis performed by the UTïŹt Collaboration within the Standard Model (SM) and beyond. Within the SM, combining the direct measurements on sides and angles, the UT turns out to be over-constrained in a consistent way, with some tension due to recently included contributions to the theoretical prediction of ΔK and the updated lattice average for BK. Generalising the UT analysis to investigate NP effects, constraints on bâs transitions are also included and both CKM and NP parameters are ïŹtted simultaneously. The most interesting results on the bâs transitions come from the BsâÂŻ Bs mixing and the di-muon charge asymmetry with updated results recently available from the Tevatron experiments. We observe a departure from the SM in the Bs sector
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