A lattice study of the two-dimensional Wess Zumino model

We present results from a numerical simulation of the two-dimensional Euclidean Wess-Zumino model. In the continuum the theory possesses N=1 supersymmetry. The lattice model we employ was analyzed by Golterman and Petcher in \cite{susy} where a perturbative proof was given that the continuum supersymmetric Ward identities are recovered without finite tuning in the limit of vanishing lattice spacing. Our simulations demonstrate the existence of important non-perturbative effects in finite volumes which modify these conclusions. It appears that in certain regions of parameter space the vacuum state can contain solitons corresponding to field configurations which interpolate between different classical vacua. In the background of these solitons supersymmetry is partially broken and a light fermion mode is observed. At fixed coupling the critical mass separating phases of broken and unbroken supersymmetry appears to be volume dependent. We discuss the implications of our results for continuum supersymmetry breaking.Comment: 32 pages, 12 figure

Exact Lattice Supersymmetry: the Two-Dimensional N=2 Wess-Zumino Model

We study the two-dimensional Wess-Zumino model with extended N=2 supersymmetry on the lattice. The lattice prescription we choose has the merit of preserving {\it exactly} a single supersymmetric invariance at finite lattice spacing $a$. Furthermore, we construct three other transformations of the lattice fields under which the variation of the lattice action vanishes to $O(ga^2)$ where $g$ is a typical interaction coupling. These four transformations correspond to the two Majorana supercharges of the continuum theory. We also derive lattice Ward identities corresponding to these exact and approximate symmetries. We use dynamical fermion simulations to check the equality of the massgaps in the boson and fermion sectors and to check the lattice Ward identities. At least for weak coupling we see no problems associated with a lack of reflection positivity in the lattice action and find good agreement with theory. At strong coupling we provide evidence that problems associated with a lack of reflection positivity are evaded for small enough lattice spacing.Comment: 29 pages, 10 figures. New results at strong coupling added. Minor corrections to text and one reference added. Version to appear in Phys. Rev.

Search for a Scalar Bottom Quark with Mass 3.5-4.5 GeV/c2c^{2}

We report on a search for a supersymmetric $\tilde{B}$ meson with mass between 3.5 and 4.5 GeV/$c^2$ using 4.52 ${\rm fb}^{-1}$ of integrated luminosity produced at $\sqrt{s}=10.52$ GeV, just below the $e^+e^-\to B\bar{B}$ threshold, and collected with the CLEO detector. We find no evidence for a light scalar bottom quark.Comment: 10 pages postscript, also available through http://w4.lns.cornell.edu/public/CLN

Клинико-лабораторные различия у больных с локализованной и генерализованной формами саркомы Капоши

The objective: to evaluate clinical and laboratory parameters in local and generalized forms of Kaposi sarcoma (KS) in HIV infected patients to detect predictors of generalized forms of the disease.Subjects and methods. Case histories of 58 HIV infected patients with KS at the age from 28 to 80 years old were respectively analyzed; they all received treatment in National Medical Research Center of Phthisiopulmonology and Infectious Diseases of the Russian Ministry of Health in 2018-2020. Cases were divided into 2 groups depending on KS manifestations. LF group (local form of KS, n = 28) included the patients with skin lesions; GF group (generalized form of KS, n = 30) included patients with skin lesions and one or several lesions in the other sites: the mucous membrane of gastrointestinal tract, the mucous membrane of tracheobronchial tree, and lung parenchyma.Results. Patients with the generalized form of KS had a higher frequency of skin lesions on the body (pχ2 = 0.036), face (pχ2 = 0.033), and multiple sites (pχ2 = 0.018). Patients from both groups had low CD4+ count, but it was more severe in GF group (pχ2 = 0.027) with a significant increase of the viral load (pχ2 = 0.047). The predictors of the generalized form of KS are the following: the presence of specific lesions on the skin of body, face and multiple localizations, CD4 level below 125 cells/mcL, increase in the viral load above 5.3log10 copies/ml, reduction of erythrocytes level below 3.1 × 1012 cells/L. Among 24 patients with KS who had 4-6 predictors, 19 (79.2%) had the generalized form. Among KS patients with not a single predictor, there were no cases of generalized form, as well as there were no cases of local forms among patients who had 5 and 6 predictors.Цель: оценить клинико-лабораторные параметры при локализованной и генерализованной формах саркомы Капоши (СК) у пациентов с ВИЧ-инфекцией для определения предикторов генерализованных форм заболевания.Материалы и методы. Ретроспективно проанализированы истории болезни 58 пациентов с ВИЧ-инфекцией и СК в возрасте от 28 до 80 лет, получавших лечение в ФГБУ «НМИЦ ФПИ» Минздрава России в 2018-2020 гг. Сформированы две группы в зависимости от проявлений СК. В группу ЛФ (локализованная форма СК, n = 28) включены пациенты с поражением кожи, в группу ГФ (генерализованная форма СК, n = 30) ‒ с сочетанием поражений кожи с одним или несколькими поражениями других локализаций: слизистая оболочка желудочно-кишечного тракта, слизистая оболочка трахеобронхиального дерева, паренхима легких.Результаты. У пациентов с генерализованной формой СК отмечалось увеличение частоты поражения кожи на туловище (pχ2 = 0,036), лице (pχ2 = 0,033), а также множественность локализаций (pχ2 = 0,018). Для пациентов обеих групп было характерно снижение уровня CD4+-лим- фоцитов, но более выраженное в группе ГФ (pχ2 = 0,027) при существенном увеличении вирусной нагрузки (pχ2 = 0,047). Предикторами генерализованной формы СК являются: наличие специфических образований на коже туловища, лица и множественных локализаций, снижение уровня CD4 Т-лимфоцитов ниже 125 кл/мкл, повышение вирусной нагрузки выше 5,3 log10 копий/мл, снижение уровня эритроцитов ниже 3,1 × 1012 кл/л. Среди 24 пациентов с СК, имевших 4-6 предикторов, 19 (79,2%) были с генерализованной формой. Среди пациентов с СК, не имевших ни одного предиктора, случаев генерализованной формы не было, также как не было случаев локализованной формы среди пациентов, имевших 5 и 6 предикторов

Study of Charmless Hadronic B Meson Decays to Pseudoscalar-Vector Final States

We report results of searches for charmless hadronic B meson decays to pseudoscalar(pi^+-,K^+-,Pi^0 or Ks^0)-vector(Rho, K* or Omega) final states. Using 9.7 million BBbar pairs collected with the CLEO detector, we report first observation of B^- --> Pi^-Rho^0, B^0 --> Pi^+-Rho^-+ and B^- --> Pi^-Omega, which are expected to be dominated by hadronic b --> u transitions. The measured branching fractions are (10.4+3.3-3.4+-2.1)x10^-6, (27.6+8.4-7.4+-4.2)x10^-6 and (11.3+3.3-2.9+-1.4)x10^-6, respectively. Branching fraction upper limits are set for all the other decay modes investigated.Comment: 10 pages postscript, also available through http://w4.lns.cornell.edu/public/CLN

Observation of New States Decaying into Λc+π−π+\Lambda_{c}^{+}\pi^{-}\pi^{+}

Using 13.7 fb^{-1} of data recorded by the CLEO detector at CESR, we investigate the spectrum of charmed baryons which decay into Lambda_c^+ pi^- pi^+ and are more massive than the Lambda_{c1} baryons. We find evidence for two new states: one is broad and has an invariant mass roughly 480 MeV above that of the Lambda_c^+; the other is narrow with an invariant mass of 596 +- 1 +- 2 MeV above the Lambda_c^+ mass. These results are preliminary.Comment: 11 pages postscript, also available through http://w4.lns.cornell.edu/public/CLN

First Observation of the Σc∗+\Sigma_{c}^{*+} Baryon and a New Measurement of the Σc+\Sigma_{c}^{+} Mass

Using data recorded with the CLEO II and CLEO II.V detector configurations at the Cornell Electron Storage Rings, we report the first observation and mass measurement of the $\Sigma_c^{*+}$ charmed baryon, and an updated measurement of the mass of the $\Sigma_c^+$ baryon. We find $M(\Sigma_c^{*+})-M(\Lambda_c^+)$= 231.0 +- 1.1 +- 2.0 MeV, and $M(\Sigma_c^{+})-M(\Lambda_c^+)$= 166.4 +- 0.2 +- 0.3 MeV, where the errors are statistical and systematic respectively.Comment: 8 pages postscript, also available through http://w4.lns.cornell.edu/public/CLN

Measurements of the Mass, total Width and Two-Photon Partila Width of the ηc\eta_{c} Meson

Using 13.4 $fb^{-1}$ of data collected with the CLEO detector at the Cornell Electron Storage Ring, we have observed 300 events for the two-photon production of ground-state pseudo-scalar charmonium in the decay $\eta_c$ -> $K_S K^{\mp} \pi^{\pm}$. We have measured the $\eta_c$ mass to be (2980.4 +- 2.3 (stat) +- 0.6 (sys)) MeV and its full width as (27.0 +- 5.8 (stat) +- 1.4 (sys)) MeV. We have determined the two-photon partial width of the $\eta_c$ meson to be (7.6 +- 0.8 (stat) +- 0.4 (sys) +- 2.3 (br)) keV, with the last uncertainty associated with the decay branching fraction.Comment: 9 pages postscript, also available through http://w4.lns.cornell.edu/public/CLN

Measurement of the B0 and B+ meson masses from B0 -> psi(') K_S and B+ -> psi(') K+ decays

Using 9.6 million B meson pairs collected with the CLEO detector, we have fully reconstructed 135 B0 -> psi(') K_S and 526 B+ -> psi(') K+ candidates with very low background. We fitted the psi(')K invariant mass distributions of these B meson candidates and measured the masses of the neutral and charged B mesons to be M(B0)=5279.1+-0.7[stat]+-0.3[syst] MeV/c^2 and M(B+)=5279.1+-0.4[stat]+-0.4[syst] MeV/c^2. The precision is a significant improvement over previous measurements.Comment: 2 typographic errors corrected; 11 pages, 2 figures; also available through http://www.lns.cornell.edu/public/CLNS/CLEO.htm

Study of exclusive two-body B0 meson decays to charmonium

We present a study of three B0 decay modes useful for time-dependent CP asymmetry measurements. From a sample of 9.7 million B meson pairs collected with the CLEO detector, we have reconstructed B0 -> J/psi K0S, B0 -> chi_c1 K0S, and B0 -> J/psi pi0 decays. The latter two decay modes have been observed for the first time. We describe a K0S -> pi0 pi0 detection technique and its application to the reconstruction of the decay B0 -> J/psi K0S. Combining the results obtained using K0S -> pi+ pi- and K0S -> pi0 pi0 decays, we determine Br(B0 -> J/psi K0) = (9.5 +- 0.8 +- 0.6)*10^-4, where the first uncertainty is statistical and the second one is systematic. We also obtain Br(B0 -> chi_c1 K0)= (3.9 +1.9/-1.3 +- 0.4)*10^-4 and Br(B0 -> J/psi pi0) = (2.5 +1.1/-0.9 +- 0.2)*10^-5.Comment: 11 pages, 2 figures, submitted to Phys. Rev.