932 research outputs found
Vector and scalar form factors for K- and D-meson semileptonic decays from twisted mass fermions with Nf = 2
We present lattice results for the form factors relevant in the K -> pion and
D -> pion semileptonic decays, obtained from simulations with two flavors of
dynamical twisted-mass fermions and pion masses as light as 260 MeV. For K ->
pion decays we discuss the estimates of the main sources of systematic
uncertainties, including the quenching of the strange quark, leading to our
final result f+(0) = 0.9560 (57) (62). Combined with the latest experimental
data, our value of f+(0) implies for the CKM matrix element |Vus| the value
0.2267 (5) (20) consistent with the first-row CKM unitarity. For D -> pion
decays the application of Heavy Meson Chiral Perturbation Theory allows to
extrapolate our results for both the scalar and the vector form factors at the
physical point with quite good accuracy, obtaining a nice agreement with the
experimental data. In particular at zero-momentum transfer we obtain f+(0) =
0.64 (5).Comment: 8 pages, 4 figures, 1 table, proceedings of the XXVII Int'l Symposium
on Lattice Field Theory (LAT2009), July 26-31 2009, Peking University,
Beijing (China
Average up/down, strange and charm quark masses with Nf=2 twisted mass lattice QCD
We present a high precision lattice calculation of the average up/down,
strange and charm quark masses performed with Nf=2 twisted mass Wilson
fermions. The analysis includes data at four values of the lattice spacing and
pion masses as low as ~270 MeV, allowing for accurate continuum limit and
chiral extrapolation. The strange and charm masses are extracted by using
several methods, based on different observables: the kaon and the eta_s meson
for the strange quark and the D, D_s and eta_c mesons for the charm. The quark
mass renormalization is carried out non-perturbatively using the RI-MOM method.
The results for the quark masses in the MSbar scheme read: m_ud(2 GeV)= 3.6(2)
MeV, m_s(2 GeV)=95(6) MeV and m_c(m_c)=1.28(4) GeV. We also obtain the ratios
m_s/m_ud=27.3(9) and m_c/m_s=12.0(3).Comment: 20 pages, 5 figures. Typos corrected in eqs. (15)-(17). Version
published in Phys. Rev.
Achilles Tendon Rupture: Mechanisms of Injury, Principles of Rehabilitation and Return to Play
The Achilles tendon is the thickest, strongest and largest tendon in the human body, but despite its size and tensile strength, it frequently gets injured. Achilles tendon ruptures (ATRs) mainly occur during sports activities, and their incidence has increased over the last few decades. Achilles tendon tears necessitate a prolonged recovery time, sometimes leaving long-term functional limitations. Treatment options include conservative treatment and surgical repair. There is no consensus on which is the best treatment for ATRs, and their management is still controversial. Limited scientific evidence is available for optimized rehabilitation regimen and on the course of recovery after ATRs. Furthermore, there are no universally accepted outcomes regarding the return to play (RTP) process. Therefore, the aim of this narrative review is to give an insight into the mechanism of injuries of an ATR, related principles of rehabilitation, and RTP
Quark masses with Nf=2 twisted mass lattice QCD
We present the results of the recent high precision lattice calculation of
the average up/down, strange and charm quark masses performed by ETMC with Nf=2
twisted mass Wilson fermions. The analysis includes data at four values of the
lattice spacing and pion masses as low as ~270 MeV, allowing for accurate
continuum limit and chiral extrapolation. The strange and charm masses are
extracted by using several methods, based on different observables: the kaon
and the eta_s meson for the strange quark and the D, D_s and eta_c mesons for
the charm. The quark mass renormalization is carried out non-perturbatively
using the RI-MOM method. The results for the quark masses in the MSbar scheme
read: m_ud(2 GeV)= 3.6(2) MeV, m_s(2 GeV)=95(6) MeV and m_c(m_c)=1.28(4) GeV.
We have also obtained the ratios m_s/m_ud=27.3(9) and m_c/m_s=12.0(3).
Moreover, we provide the updated result for the bottom quark mass,
m_b(m_b)=4.3(2) GeV, obtained using the method presented in 0909.3187
[hep-lat].Comment: 7 pages, 7 figures, talk given at the XXVIII International Symposium
on Lattice Field Theory (Lattice 2010), June 14-19 2010, Villasimius, Ital
The effects of sars-cov-2 pandemic countermeasures on patients receiving infiltrative treatment for musculoskeletal disorders: A study from an italian cohort
SUMMARY Background. COVID-19 outbreak had a massive worldwide impact and several countermeasures to contain its spread have been adopted, such as the interruption of non-urgent outpatient clinics. We wanted to describe the effects of the national lock-down on the well-being of a cohort of Italian patients with musculoskeletal disorders receiving infiltrative treatment. Methods. 40 patients who received intra-or peri-articular treatment were surveyed using a structuralised questionnaire that assessed their well-being during the first national lockdown. Results. 24 out of 40 patients (60%) did not come back after the re-opening of the Clinic because they were afraid of the pandemic. Of these 24 patients, the 83.3% noticed increased pain and stiffness in the joint. Due to the lockdown, the patient’s quality of life was reduced by 61.66 ± 15.72%. After the lockdown, for the 92% of patients, the infiltrative treatment was perceived as more important than before, the 83% of patients perceived long-term security of infiltrative therapy availability as very important, and the 72% of the patients perceived the lockdown as inadequate. Conclusions. The infiltrative outpatient clinic’s interruption was seen to significant-ly worsen the physical condition of subjects with musculoskeletal disorders, with an important increase in both articular pain and stiffness. Therefore, any kind of infiltra-tive treatment suspension or delay should be avoided
Dark Matter and Dark Energy via Non-Perturbative (Flavour) Vacua
A non-perturbative field theoretical approach to flavour physics
(Blasone-Vitiello formalism) has been shown to imply a highly non-trivial
vacuum state. In a previous work, we implemented the approach on a simple
supersymmetric model (free Wess-Zumino), with flavour mixing, which was
regarded as a model for free neutrinos and sneutrinos. The resulting effective
vacuum (called "flavour vacuum") was found to be characterized by a strong SUSY
breaking. In this paper we explore the phenomenology of the model and we argue
that the flavour vacuum is a consistent source for both Dark Energy (thanks to
the bosonic sector of the model) and Dark Matter (via the fermionic one). Quite
remarkably, besides the parameters connected with neutrino physics, in this
model no other parameters have been introduced, possibly leading to a
predictive theory of Dark Energy/Matter. Despite its oversimplification, such a
toy model already seems capable to shed some light on the observed energy
hierarchy between neutrino physics, Dark Energy and Dark Matter. Furthermore,
we move a step forth in the construction of a more realistic theory, by
presenting a novel approach for calculating relevant quantities and hence
extending some results to interactive theories, in a completely
non-perturbative way.Comment: 14 pages, 2 figure
The impact of SuperB on flavour physics
This report provides a succinct summary of the physics programme of SuperB,
and describes that potential in the context of experiments making measurements
in flavour physics over the next 10 to 20 years. Detailed comparisons are made
with Belle II and LHCb, the other B physics experiments that will run in this
decade. SuperB will play a crucial role in defining the landscape of flavour
physics over the next 20 years.Comment: 20 pages, 6 figure
Prone positioning and convalescent plasma therapy in a critically ill pregnant woman with COVID-19
Prone positioning is feasible in pregnancy and may have contributed to the positive outcome in this case. Doctors should not be reluctant to move a patient to a prone position just because they are pregnant
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