475 research outputs found
CP Test in J/Psi -> gamma phi phi Decay
We propose to test CP symmetry in the decay \jp\to \gamma \phi\phi, for
which large data sample exists at BESII, and a data sample of
's will be collected with BESIII and CLEO-C program. We suggest some CP
asymmetries in this decay mode for CP test. Assuming that CP violation is
introduced by the electric- and chromo-dipole moment of charm quark, these CP
asymmetries can be predicted by using valence quark models. Our work shows a
possible way to get information about the electric- and chromo-dipole moment of
charm quark, which is little known. Our results show that with the current data
sample of , electric- and chromo-dipole moment can be probed at order
of . In the near future with a data sample, these
moments can be probed at order of .Comment: Misprints corrected. To appear in Phys. Lett.
Pulmonary function is associated with distal aortic calcium, not proximal aortic distensibility. MESA lung study
Forced expiratory volume in one second strongly predicts mortality from cardiovascular disease. FEV1 has been associated with aortic stiffness a strong independent predictor of cardiovascular mortality. However, the anatomical site and possible mechanisms linking aortic stiffness and lung function are unknown. We therefore examined if FEV1 and CT percent emphysema were associated with calcification of the abdominal aorta or reduced distensibility of the proximal thoracic aorta.The Multi-Ethnic Study of Atherosclerosis (MESA) measured aortic calcification on cardiac and abdominal CT scans and proximal aortic distensibility using magnetic resonance among participants aged 45–84 years without clinical cardiovascular disease. Spirometry was measured following ATS/ERS guidelines and percent emphysema was measured in the lung fields of cardiac CT scans. Multivariate analyses adjusted for age, sex, race/ethnicity and cardiovascular risk factors. Of 1,917 participants with aortic distensibility measures, 13% were current and 38% were former smokers. Eighteen percent had airflow limitation without asthma. FEV1 was associated with the extent of distal aortic calcification (0.76; 95%CI 0.60–0.97, p = 0.02) but not proximal aortic calcification or proximal aortic distensibility (−0.04 mmHg−1; 95%CI −0.16–0.09 mmHg−1, p = 0.60). Percent emphysema was associated with neither measure. FEV1 was associated with severity of distal aortic calcification where it was present independently of smoking and other cardiovascular risk factors but not with distensibility or calcification of the proximal aorta
CP violation in a multi-Higgs doublet model with flavor changing neutral current
We study CP violation in a multi-Higgs doublet model based on a horizontal symmetry where CKM phase is not the principal source of CP
violation. We consider two mechanisms for CP violation in this model: a) CP
violation due to complex Yukawa couplings; and b) CP violation due to
scalar-pseudoscalar Higgs boson mixings. Both mechanisms can explain the
observed CP violation in the neutral Kaon system. due to
neutral Higgs boson exchange is small in both mechanisms, but charged Higgs
boson con- tributions can be as large as for a), and for
b). CP violation in the neutral B system is, however, quite different from the
Minimal Standard
Model. The neutron Electric Dipole Moment can be as large as the present ex-
perimental bound, and can be used to constrain charged Higgs boson masses.
The electron
EDM is one order of magnitude below the experimental bound in case b) and
smaller in case a).Comment: 22 pages, Revtex, OITS-52
60 million years of glaciation in the Transantarctic Mountains
The Antarctic continent reached its current polar location ~83 Ma and became shrouded by ice sheets ~34 Ma, coincident with dramatic global cooling at the Eocene-Oligocene boundary. However, it is not known whether the first Antarctic glaciers formed immediately prior to this or were present significantly earlier. Here we show that mountain glaciers were likely present in the Transantarctic Mountains during the Late Palaeocene (~60–56 Ma) and middle Eocene (~48–40 Ma). Temperate (warm-based) glaciers were prevalent during the Late Eocene (~40–34 Ma) and, in reduced numbers, during the Oligocene (~34–23 Ma), before larger, likely cold-based, ice masses (including ice sheets) dominated. Some temperate mountain glaciers were present during the Miocene Climatic Optimum (~15 Ma), before a widespread switch to cold-based glaciation. Our findings highlight the longevity of glaciation in Antarctica and suggest that glaciers were present even during the Early-Cenozoic greenhouse world
Mapping alveolar oxygen partial pressure in COPD using hyperpolarized helium-3: the multi-ethnic study of atherosclerosis (MESA) COPD study
Chronic obstructive pulmonary disease (COPD) and emphysema are characterized by functional and structural damage which increases the spaces for gaseous diffusion and impairs oxygen exchange. Here we explore the potential for hyperpolarized (HP) 3He MRI to characterize lung structure and function in a large-scale population-based study. Participants (n = 54) from the Multi-Ethnic Study of Atherosclerosis (MESA) COPD Study, a nested case-control study of COPD among participants with 10+ packyears underwent HP 3He MRI measuring pAO2, apparent diffusion coefficient (ADC), and ventilation. HP MRI measures were compared to full-lung CT and pulmonary function testing. High ADC values (>0.4 cm2/s) correlated with emphysema and heterogeneity in pAO2 measurements. Strong correlations were found between the heterogeneity of global pAO2 as summarized by its standard deviation (SD) (p < 0.0002) and non-physiologic pAO2 values (p < 0.0001) with percent emphysema on CT. A regional study revealed a strong association between pAO2 SD and visual emphysema severity (p < 0.003) and an association with the paraseptal emphysema subtype (p < 0.04) after adjustment for demographics and smoking status. HP noble gas pAO2 heterogeneity and the fraction of non-physiological pAO2 results increase in mild to moderate COPD. Measurements of pAO2 are sensitive to regional emphysematous damage detected by CT and may be used to probe pulmonary emphysema subtypes. HP noble gas lung MRI provides non-invasive information about COPD severity and lung function without ionizing radiation
Developments in the efficiency of the Malaysian banking sector: the impacts of financial disruptions and exchange rate regimes
In the mid-1990s, East Asian countries have experienced severe financial crisis that were followed by deep economic downturns. A variety of methodologies have been used to explain the Asian financial crisis. However, the impact of the Asian financial crisis of 1997 on the efficiency of the banking sector has not been studied yet. The present article attempts to provide new empirical evidence on the efficiency of the Malaysian banking sector around the Asian financial crisis. The efficiency estimates of individual banks are evaluated by using the non-parametric data envelopment analysis (DEA) method. The results indicate that the foreign banks have exhibited higher technical efficiency compared to their domestic bank counterparts. However, the results suggest that the foreign banks were severely affected by the Asian financial crisis, implying that the foreign banks are not insulated from unexpected events like the Asian financial crisis of 1997
Mucin concentrations and peripheral airway obstruction in chronic obstructive pulmonary disease
Recent studies have revealed that increased airway mucin concentrations in chronic obstructive pulmonary disease (COPD) slow mucociliary clearance and produce mucus adhesion with mucus plug formation (1). Furthermore, data from SPIROMICS (Subpopulations and Intermediate Outcomes in COPD Study) demonstrated an association between induced sputum (IS) mucin concentrations and measures of airflow obstruction, e.g., FEV1 and FEV1/FVC (2). Peripheral airways are the earliest and dominant sites of airflow obstruction in COPD, and Hogg and colleagues demonstrated that intraluminal mucus plugs contribute a major component to peripheral airway obstruction (3). For development of targeted therapies, it is important to understand whether there are associations between mucus concentrations and peripheral airway obstruction in COPD
Probing exotic phenomena at the interface of nuclear and particle physics with the electric dipole moments of diamagnetic atoms: A unique window to hadronic and semi-leptonic CP violation
The current status of electric dipole moments of diamagnetic atoms which
involves the synergy between atomic experiments and three different theoretical
areas -- particle, nuclear and atomic is reviewed. Various models of particle
physics that predict CP violation, which is necessary for the existence of such
electric dipole moments, are presented. These include the standard model of
particle physics and various extensions of it. Effective hadron level combined
charge conjugation (C) and parity (P) symmetry violating interactions are
derived taking into consideration different ways in which a nucleon interacts
with other nucleons as well as with electrons. Nuclear structure calculations
of the CP-odd nuclear Schiff moment are discussed using the shell model and
other theoretical approaches. Results of the calculations of atomic electric
dipole moments due to the interaction of the nuclear Schiff moment with the
electrons and the P and time-reversal (T) symmetry violating
tensor-pseudotensor electron-nucleus are elucidated using different
relativistic many-body theories. The principles of the measurement of the
electric dipole moments of diamagnetic atoms are outlined. Upper limits for the
nuclear Schiff moment and tensor-pseudotensor coupling constant are obtained
combining the results of atomic experiments and relativistic many-body
theories. The coefficients for the different sources of CP violation have been
estimated at the elementary particle level for all the diamagnetic atoms of
current experimental interest and their implications for physics beyond the
standard model is discussed. Possible improvements of the current results of
the measurements as well as quantum chromodynamics, nuclear and atomic
calculations are suggested.Comment: 46 pages, 19 tables and 16 figures. A review article accepted for
EPJ
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