Distribution Amplitudes of Heavy Hadrons: Theory and Applications

The physics of heavy quarks becomes a very reach area of study thanks to an excellent operation of hadron colliders and $B$-factories and exciting results from them. Experimental data obtained allows to get some information about the heavy hadron dynamics. In this case, the models for the heavy hadron wave-functions are required to do theoretical predictions for concrete processes under study. In many cases, the light-cone description is enough to obtain theoretical estimates for heavy hadron decays. A discussion of the wave-functions of the $B$-meson and heavy bottom baryons in terms of the light-cone distribution amplitudes is given in this paper. Simple models for the distribution amplitudes are presented and their scale dependence is discussed. Moments of the distribution amplitudes which are entering the branching fractions of radiative, leptonic and semileptonic $B$-mesons decays are also briefly discussed.Comment: 17 pages, 4 figures, lecture at the Helmholtz International Summer School and Dubna International Advanced School on Theoretical Physics "Quantum Field Theory at the Limits: from Strong Fields to Heavy Quarks", JINR, Dubna, Russia, July 18--30, 201

Estimating Hedonic Price Indices for Personal Computers in Russia

Economist have noted for decades that Consumer Price Index (CPI) in the developed countries is overstating inflation by 0,5-2,0% per year. A significant part of such a bias is found to be caused by the presence of technology products and differentiated products in CPI. An increasing weight of these products in the Russian CPI may also lead to a substantial upward bias. Nowadays hedonic indices are believed to be the most efficient way to reduce the bias. Following Triplett we have developed the taxonomy of hedonic price indices within the “direct approach”. This first step is essential in constructing a detailed set of hedonic price indices. They can be used in two ways: to estimate the bias in CPI and to elaborate alternative official price indices for IT-products. We've estimated 11% fall of price for personal computers in 2005 with the usage of hedonic price indices, a 11-23% positive bias in price index for PC in Russia was also calculated. We also have found that Russian CPI could be upward biased by 0,12-0,23% per year due to new goods and quality change effects for PC.Hedonic; Price index; bias; CPI; PC; inflation; new economy

Prognostic importance of acute heart failure persistence in patients with ST-elevation myocardial infarction

Introduction: Acute heart failure (AHF) is one of the most frequent complication of acute myocardial infarction (AMI). It is not only associated with a several-fold increase of in-hospital mortality but also, worsens the long-term survival in comparison to those without AHF. The AHF is observed to be more in AMI patients whose in-hospital stay is more than 3 days. The clinical implications and prognostic accuracy of the AHF term in the setting of AMI are yet unknown. Methods: We observed 1,104 consecutive cardiac care patients, who were admitted with ST-elevation AMI (STEMI). They were divided into groups according to the AHF presence {AHF(+) n=334 and AHF(-) n=764}. Among 334 AHF(+) patients: 252 patients were found to have a transient AHFt(+), whereas 82 of AHF(+) patients had persistent AHFp(+) during in-hospital period.  Patients' baseline characteristics, blood analysis, left ventricle (LV) and renal function data were assessed and analyzed on the admission day and 10th day post-admission. The follow-up was conducted on the 30th day and after 2 years. Results. STEMI patients accompanied by AHF(+) were older, presented mostly with anterior AMI (p<0.01), had lower LV ejection fraction (EF) (p<0.01) and a higher heart rate (p<0.05). Their rates of comorbidities and of in-hospital complications such as recurrent angina, reinfarction, LV aneurism were higher in comparision to AHF(-) patients. AHFp(+) patients had the shortest time from symptoms onset before thrombolysis in comparision to AHFt(+) and AHF(-) groups. Partial recovery of cardiac function according to Left ventricular ejection fraction (LVEF) and end-systolic volume index, occurred mainly in AHF(-) and AHFt(+) patients on the 10th day post-admission, but not in AHFp(+). STEMI patients with AHFp(+) demonstrated a larger infarct size, higher C-reactive protein and VGEF level, fasting glucose and heart rate on admission, higher erythrocyte sedimentation rate, absence of heart rate normalization on the 10th day post-admission. All of these markers were the signs of severe myocardial damage and inflammation, which can reflect worse recovery in AHF patients despite optimal management. Patients with AHF(+) had renal dysfunction on admission while its creatinine clearance (CrCl) decreased during the in-hospital period which is the reflection of a poor prognosis. Сardiovascular mortality and non-fatal MI were significantly higher in the AHFp(+) group as compared to the AHFt(+) and the AHF(–) groups during the 30 days and 2 years of follow-up. Conclusion: The AHF is a frequent STEMI complication. AHF lasting >3 days had worse short- and long-term prognosis. Therefore, an aggressive strategy should be recommended particularly in patients who have clinical signs and symptoms of persistent AHF

Markers of Poor Prognosis in Non-ST Segment Elevation Acute Coronary Syndromes Without Revascularization: A 3-Year Survival Analysis

Introduction: The non-ST elevation acute coronary syndrome (NSTE-ACS) account for more than 50% of the total number of patients with ACS. The mortality rates after NSTEMI are not significantly different when compared with patients with ST-segment elevation myocardial infarction. Aim: The aim of the present study was to investigate whether the assessment of clinical, laboratory and instrumental data during hospital stay provide any additional independent information in predicting the 3-year major cardiac events after NSTE-ACS. Methods: We observed 490 consecutive patients, who were admitted to the emergency cardiology department with NSTE-ACS. The patients' baseline characteristics, blood analysis, left ventricle (LV) and renal function data were assessed and analyzed. The median follow‑up time was 36 months. The endpoint was cardiovascular death. Results: The results of our study show that the risk of cardiovascular death during the three years follow-up after multivariate adjustment increases with older age (> 64 years), history of diabetes, prior myocardial infarction and history of angina pectoris, lower ejection fraction (<50%), degree of myocardial hypertrophy (the thickness of the interventricular septum >1.25 mm) of the LV and the degree of diastolic dysfunction (E-wave deceleration time (DT) < 150 ms), silent myocardial ischemia during first 24-hours, high pulse pressure on Day 1 (>49 mm Hg), glucose level > 7.5 mmol/l on admission and moderate kidney dysfunction (CrCl <60 ml/min). Conclusion: In patients with NSTE-ACS, we report the cardiovascular death risk factors within the 3-year follow-up period in the present study. We thus conclude that it is important to identify the patients with high risk of future cardiovascular complications

Branching Fraction of the Decay B+→π+τ+τ−B^+ \to \pi^+ \tau^+ \tau^- and Lepton Flavor Universality Test via the Ratio Rπ(τ/μ)R_\pi (\tau/\mu)

Among (semi)leptonic rare $B$-decays induced by the $b \to d$ flavor changing neutral current, the decay $B^+ \to \pi^+ \mu^+ \mu^-$ is the only one observed so far experimentally. Related decays involving the $e^+e^-$ and $\tau^+ \tau^-$ pairs are the targets for the ongoing experiments at the LHC, in particular LHCb, and Belle II. The muonic and electronic semileptonic decays have almost identical branching fractions in the Standard Model (SM). However, the tauonic decay $B^+ \to \pi^+ \tau^+ \tau^-$ differs from the other two due to the higher reaction threshold which lies slightly below the $\psi (2S)$-resonance. We present calculations of the ditauon ($\tau^+ \tau^-$) invariant-mass distribution and the branching fraction ${\rm Br} (B^+ \to \pi^+ \tau^+ \tau^-)$ in the SM based on the Effective Electroweak Hamiltonian approach, taking into account also the so-called long-distance contributions. The largest theoretical uncertainty in the short-distance part of the decay rates is due to the $B \to \pi$ form factors, which we quantify using three popular parametrizations. The long-distance contribution can be minimized by a cut on the ditauon mass $m_{\tau^+ \tau^-} > M_{\psi (2S)}$. Once available, the branching fractions in the tauonic and muonic (and electronic) modes provide stringent test of the lepton flavor universality in the $b \to d$ transitions. We illustrate this by calculating the ratio $R_\pi (\tau/\mu) \equiv {\rm Br} (B^+ \to \pi^+ \tau^+ \tau^-)/{\rm Br} (B^+ \to \pi^+ \mu^+ \mu^-)$ in the SM for the total and binned ratios of the branching fractions.Comment: 11 pages, 5 figures, 11 table

Prospects of discovering stable double-heavy tetraquarks at a Tera-ZZ factory

Motivated by a number of theoretical considerations, predicting the deeply bound double-heavy tetraquarks $T^{\{bb\}}_{[\bar u \bar d]}$, $T^{\{bb\}}_{[\bar u \bar s]}$ and $T^{\{bb\}}_{[\bar d \bar s]}$, we explore the potential of their discovery at Tera-$Z$ factories. Using the process $Z \to b \bar b b \bar b$, we calculate, employing the Monte Carlo generators MadGraph5$\_$aMC@NLO and Pythia6, the phase space configuration in which the~$b b$ pair is likely to fragment as a diquark. In a jet-cone, defined by an invariant mass interval $m_{bb} < M_{T^{\{bb\}}_{[\bar q \bar q']}} + \Delta M$, the sought-after tetraquarks $T^{\{bb\}}_{[\bar q \bar q^\prime]}$ as well as the double-bottom baryons,~$\Xi_{bb}^{0,-}$, and $\Omega_{bb}^-$, can be produced. Using the heavy quark--diquark symmetry, we estimate $\mathcal{B} (Z \to T^{\{bb\}}_{[\bar u \bar d]} + \; \bar b \bar b) = (1.4^{+1.1}_{-0.5}) \times 10^{-6}$, and about a half of this for the $T^{\{bb\}}_{[\bar{u}\bar{s}]}$ and $T^{\{bb\}}_{[\bar d \bar s]}$. We also present an estimate of their lifetimes using the heavy quark expansion, yielding $\tau(T^{\{bb\}}_{[\bar q \bar q^\prime]}) \simeq 800$~fs. Measuring the tetraquark masses would require decays, such as $T^{\{bb\} -}_{[\bar u \bar d]} \to B^- D^- \pi^+$, $T^{\{bb\} -}_{[\bar u \bar d]} \to J/\psi \overline K^0 B^-$, $T^{\{bb\} -}_{[\bar u \bar d]} \to J/\psi K^- \overline B^0$, $T^{\{bb\} -}_{[\bar u \bar s]} \to \Xi_{bc}^0 \Sigma^-$, and $T^{\{bb\} 0}_{[\bar d \bar s]} \to \Xi_{bc}^0 \bar\Sigma^0$, with subsequent decay chains in exclusive non-leptonic final states. We estimate a couple of the decay widths and find that the product branching ratios do not exceed~$10^{-5}$. Hence, a good fraction of these modes will be required for a discovery of $T^{\{bb\}}_{[\bar q \bar q']}$ at a Tera-$Z$ factory.Comment: 11 pages, 11 figures; v2: version to appear in PL

Эконометрические оценки гедонических индексов цен на персональные компьютеры в России: пример рынка г. Екатеринбурга

Economist have noted for decades that Consumer Price Index (CPI) in the developed countries is overstating inflation by 0,5-2,0% per year. A significant part of such a bias is found to be caused by the presence of technology products and differentiated products in CPI. An increasing weight of these products in the Russian CPI may also lead to a substantial upward bias. Nowadays hedonic indices are believed to be the most efficient way to reduce the bias. Following Triplett we have developed the taxonomy of hedonic price indices within the “direct approach”. This first step is essential in constructing a detailed set of hedonic price indices. They can be used in two ways: to estimate the bias in CPI and to elaborate alternative official price indices for IT-products. We've estimated 11% fall of price for personal computers in 2005 with the usage of hedonic price indices, a 11-23% positive bias in price index for PC in Russia was also calculated. We also have found that Russian CPI could be upward biased by 0,12-0,23% per year due to new goods and quality change effects for PC