46 research outputs found

    The Nambu sum rule and the relation between the masses of composite Higgs bosons

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    We review the known results on the bosonic spectrum in various NJL models both in the condensed matter physics and in relativistic quantum field theory including 3^3He-B, 3^3He-A, the thin films of superfluid He-3, and QCD (Hadronic phase and the Color Flavor Locking phase). Next, we calculate bosonic spectrum in the relativistic model of top quark condensation suggested in \cite{Miransky}. In all considered cases the sum rule appears that relates the masses (energy gaps) MbosonM_{boson} of the bosonic excitations in each channel with the mass (energy gap) of the condensed fermion MfM_f as Mboson2=4Mf2\sum M_{boson}^2 = 4 M_f^2. Previously this relation was established by Nambu in \cite{Nambu} for 3^3He-B and for the s - wave superconductor. We generalize this relation to the wider class of models and call it the Nambu sum rule. We discuss the possibility to apply this sum rule to various models of top quark condensation. In some cases this rule allows to calculate the masses of extra Higgs bosons that are the Nambu partners of the 125 GeV Higgs.Comment: Latex, 15 page

    Performance and Fundamental Processes at Low Energy in a Two-Phase Liquid Xenon Dark Matter Detector

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    We extend the study of the performance of a prototype two-phase liquid xenon WIMP dark matter detector to recoil energies below 20 keV. We demonstrate a new method for obtaining the best estimate of the energies of events using a calibrated sum of charge and light signals and introduce the corresponding discrimination parameter, giving its mean value at 4 kV/cm for electron and nuclear recoils up to 300 and 100 keV, respectively. We show that fluctuations in recombination limit discrimination for most energies, and reveal an improvement in discrimination below 20 keV due to a surprising increase in ionization yield for low energy electron recoils. This improvement is crucial for a high-sensitivity dark matter search.Comment: 4 pages, 6 figures, submitted to DM06 conference proceedings in Nucl Phys

    Scintillation Pulse Shape Discrimination in a Two-Phase Xenon Time Projection Chamber

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    The energy and electric field dependence of pulse shape discrimination in liquid xenon have been measured in a 10 gm two-phase xenon time projection chamber. We have demonstrated the use of the pulse shape and charge-to-light ratio simultaneously to obtain a leakage below that achievable by either discriminant alone. A Monte Carlo is used to show that the dominant fluctuation in the pulse shape quantity is statistical in nature, and project the performance of these techniques in larger detectors. Although the performance is generally weak at low energies relevant to elastic WIMP recoil searches, the pulse shape can be used in probing for higher energy inelastic WIMP recoils.Comment: 7 pages, 11 figure

    Особенности финансового состояния компаний с убывающими доходами

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    The recent rise in inflation in Europe, caused by the pandemic, the increase in prices for energy resources and the violation of the logistics of energy supplies, has led to a decrease in company income. This makes it relevant to study the financial condition of companies with falling revenues. The purpose of this study is the development of tools for quantifying the impact of falling company incomes is becoming essential for making adequate management decisions. Until recently, such tools in capital structure theory did not exist. Two main theories of the capital cost and capital structure — Brusov — Filatova — Orekhova (BFO) theory and Modigliani — Miller (MM) theory — described companies with constant revenue: the first — for arbitrary age company, the second — for perpetuity companies. Within last couple years both these theories have been generalized for the case of variable revenue. In this paper the peculiar properties of the financial state of companies with falling income are studied within the modern capital cost and capital structure theory — Brusov–Filatova– Orekhova (BFO) theory, generalized for the case of variable revenue. As part of the goal, the tasks are solved to study the behavior of the main financial indicators (the cost of raising capital, the discount rate, the company’s capitalization, the cost of equity, and others), their dependence on debt financing, the age of the company in the face of declining income, which will make it possible to make adequate management decisions and reduce risks for companies.  Недавний рост инфляции в Европе, вызванный пандемией, ростом цен на энергоресурсы и нарушением логистики энергопоставок, привел к снижению доходов компаний. Это делает актуальным изучение финансового состояния компаний с падающей выручкой. Целью настоящего исследования является разработка инструментов для количественной оценки влияния падения доходов компании на ее финансовые индикаторы, что необходимо для принятия адекватных управленческих решений. До недавнего времени таких инструментов в теории структуры капитала не существовало. Две основные теории стоимости капитала и структуры капитала — Брусова–Филатовой–Ореховой (БФО) и Модильяни–Миллера (ММ) — описывали компании с постоянным доходом: первая — для компаний произвольного возраста, вторая — для бессрочных компаний. За последние пару лет обе эти теории были обобщены на случай переменных доходов. В данной работе особенности финансового состояния компаний с падающими доходами исследуются в рамках современной теории стоимости и структуры капитала — теории Брусова–Филатовой–Ореховой (БФО), обобщенной на случай переменных доходов. В рамках поставленной цели решаются задачи по изучению поведения основных финансовых показателей (стоимости привлечения капитала, ставки дисконтирования, капитализации компании, стоимости собственного капитала и других), их зависимости от заемного финансирования, возраста компании в условиях снижения доходов, что позволит принять адекватные управленческие решения и снизить риски для компаний

    Why holes are not like electrons. II. The role of the electron-ion interaction

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    In recent work, we discussed the difference between electrons and holes in energy band in solids from a many-particle point of view, originating in the electron-electron interaction, and argued that it has fundamental consequences for superconductivity. Here we discuss the fact that there is also a fundamental difference between electrons and holes already at the single particle level, arising from the electron-ion interaction. The difference between electrons and holes due to this effect parallels the difference due to electron-electron interactions: {\it holes are more dressed than electrons}. We propose that superconductivity originates in 'undressing' of carriers from bothboth electron-electron and electron-ion interactions, and that both aspects of undressing have observable consequences.Comment: Continuation of Phys.Rev.B65, 184502 (2002) = cond-mat/0109385 (2001

    First Results from the XENON10 Dark Matter Experiment at the Gran Sasso National Laboratory

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    The XENON10 experiment at the Gran Sasso National Laboratory uses a 15 kg xenon dual phase time projection chamber (XeTPC) to search for dark matter weakly interacting massive particles (WIMPs). The detector measures simultaneously the scintillation and the ionization produced by radiation in pure liquid xenon, to discriminate signal from background down to 4.5 keV nuclear recoil energy. A blind analysis of 58.6 live days of data, acquired between October 6, 2006 and February 14, 2007, and using a fiducial mass of 5.4 kg, excludes previously unexplored parameter space, setting a new 90% C.L. upper limit for the WIMP-nucleon spin-independent cross-section of 8.8 x 10^{-44} cm^2 for a WIMP mass of 100 GeV/c^2, and 4.5 x 10^{-44} cm^2 for a WIMP mass of 30 GeV/c^2. This result further constrains predictions of supersymmetric models.Comment: accepted for publication in Phys. Rev. Let

    Constraints on inelastic dark matter from XENON10

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    It has been suggested that dark matter particles which scatter inelastically from detector target nuclei could explain the apparent incompatibility of the DAMA modulation signal (interpreted as evidence for particle dark matter) with the null results from CDMS-II and XENON10. Among the predictions of inelastically interacting dark matter are a suppression of low-energy events, and a population of nuclear recoil events at higher nuclear recoil equivalent energies. This is in stark contrast to the well-known expectation of a falling exponential spectrum for the case of elastic interactions. We present a new analysis of XENON10 dark matter search data extending to Enr=75_{nr}=75 keV nuclear recoil equivalent energy. Our results exclude a significant region of previously allowed parameter space in the model of inelastically interacting dark matter. In particular, it is found that dark matter particle masses mχ150m_{\chi}\gtrsim150 GeV are disfavored.Comment: 8 pages, 4 figure

    Выбор препарата инфузионной терапии в раннем послеоперационном периоде у детей

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    The choice of drug for initial fluid therapy in the early postoperative period is important in terms of clinical efficacy and cost-effectiveness of the combination treatment.The aim of the study was to compare the effects of a succinate-containing solution and 0.9% NaCl solution when used as a drug of initial intravenous fluid therapy in early postoperative period in children.Materials and methods. A prospective randomized trial was conducted with participation of 43 patients having ASA II—III score after elective surgical interventions with a duration of 1-3 hours. In Group I («N») (n=23) the patients received continuous infusion of 0.9% NaCl solution in the early postoperative period (within 3 hours after the operation), in Group 2 («R») (n=20) continuous infusion of a succinate-containing solution was administered in 2.3 (1.6; 2.8) mode. The inter- and intragroup differences during the study were estimated by the changes of water-electrolyte and acid-base balance, basal metabolism, and phase angle (estimated integral index of cellular membranes condition) values. The data were recorded during the 5 stages of the study: 1 — immediately upon ICU admission (baseline), 2 — 60 minutes, 3 — 90 minutes, 4 — 120 minutes, 5 — 180 minutes after the ICU admission.Results. Significant differences in plasma potassium level between the groups 60 minutes (P=0.01) and 180 minutes (P=0.04) after the initiation of drugs infusion were found. In group N, at the 2nd stage, a 7% decrease in the potassium level was observed, while in group R, it increased by 2.1% as compared with the baseline. By the end of the study, potassium level decreased by 6.9% in group N and by 6.5% in group R. The intragroup differences were significant in Group N at the 2nd (P=0.02) and 5th (P=0.01) stages. In group R, no significant differences vs the baseline were found at any stage. In all cases, the values were within the reference values. In group N, at the 2nd stage the sodium concentration increased compared with the 1st stage by 2.1% (P=0.01). In group R, at the 5th stage, a significant decrease of Cl- concentration by 2.7% (P=0.01) was observed. The acid-base status showed a trend towards mixed acidosis at the 2nd stage in both groups, with the similarly significant pH reduction by 1.3% vs the baseline, whereas at 5th stage the decrease of pH was more significant in Group N (by 1.2% vs the baseline) than in Group R (by 0.9%) (P=0.01). In group N, the phase angle value was found to decrease by 8.6% at the 2nd stage and by 6% at the 5th stage (P=0.01). In group R no significant differences in the phase angle values were found.Conclusion. The succinate-containing solution has more favorable effect on the water-electrolyte and blood acid-base balance, as well as the state of cell membranes compared with the 0.9% NaCl solution.Выбор препарата стартовой инфузионной терапии в раннем послеоперационном периоде актуален с позиции клинической эффективности, определяющей также и экономическую целесообразность комплекса лечебных мероприятий.Цель исследования. Сравнительная оценка сукцинатсодержащего раствора и раствора 0,9% NaCl в качестве препарата стартовой инфузионной терапии в раннем послеоперационном периоде у детей.Материалы и методы. Провели проспективное рандомизированное исследование методом случайной выборки у 43 пациентов с оценкой по ASA II-III после плановых хирургических вмешательств, длительностью 1-3 часа. В 1-й группе «N», (n=23) дети в раннем послеоперационном периоде (в течение 3 ч после операции) получали непрерывную инфузию раствора 0,9% NaCl, во 2-й группе «R», (n=20) — инфузию в режиме 2,3 (1,6; 2,8) сукцинатсодержащим раствором. Межгрупповое и внутригрупповое различие на этапах исследования оценивали по динамике водно-электролитного и кислотно-основного состояния (КОС), основного обмена и значений фазового угла — расчетного интегрального показателя состояния мембран клеточных структур. Данные регистрировали на 5 этапах исследования: 1 — сразу при поступлении в ОРИТ (исходные данные), 2 — через 60 минут, 3 — через 90 минут, 4 — через 120 минут, 5 — через 180 минут от момента поступления в ОРИТ.Результаты. Концентрация калия в плазме крови значимо различалась между группами через 60 (p=0,01) и 180 минут (p=0,04) после начала инфузии препаратов. В группе N на 2-м этапе отмечали снижение показателя на 7%, а в группе R увеличение на 2,1%, по отношению к исходному значению. К концу исследования концентрация калия снижалась в группе N на 6,9% и в группе R — на 6,5%. Внутригрупповые различия были значимы в группе N на 2-м (p=0,02) и 5-м (p=0,01) этапах. В группе R ни на одном этапе не выявили значимых различий от исходных значений. Во всех случаях значения показателя находились в пределах референсных значений. В группе N на 2-м этапе содержание натрия достоверно повышалось от значений 1-го этапа на 2,1% (p=0,01). В группе R на 5-м этапе наблюдали значимое снижение содержания Cl- на 2,7% (p=0,01). Динамика показателей КОС характеризовалась тенденцией к смешанному ацидозу на 2-м этапе в обеих группах, отмечали одинаковое значимое снижение pH на 1,3% от исходного значения, а к 5-у этапу — снижение pH было более выражено в группе N — на 1,2% от исходного значения, в группе R — на 0,9%, соответственно (p=0,01). В группе N выявили снижение значения фазового угла на 8,6% на 2-м этапе и на 6% к 5-у этапу исследования (p=0,01). В группе R значимых различий в динамике значений фазового угла не обнаружили.Заключение. Сукцинатсодержащий раствор благоприятнее влияет на водно-электролитный баланс, КОС плазмы крови, состояние клеточных мембран в сравнении с раствором 0,9% NaCl

    Observation of Dispersion in the J=2+ Collective Modes of He-3-B by Nonlinear Acoustic Spectroscopy

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    Parametric excitation yields new results, which cannot be obtained by conventional linear spectroscopy, on the collective modes in superfluid He-3-B. In our ultrasonic experiments, performed in a chamber with four quartz crystals, we have excited the real squashing (J = 2+) modes by two simultaneous sound waves which are mutually either parallel, orthogonal, or antiparallel. Qualitatively these results are in agreement with the theoretical dispersion relation of the J = 2+ modes, and quantitatively we have been able to extract the collective-mode velocities from the line splittings in zero magnetic field
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