Alzheimer’s disease (AD) is the leading and one of the most severe forms of dementia. Molecular mechanisms underlying AD pathogenesis despite much work on this subject still remain unclear. Cleavage of amyloid precur...Alzheimer’s disease (AD) is the leading and one of the most severe forms of dementia. Molecular mechanisms underlying AD pathogenesis despite much work on this subject still remain unclear. Cleavage of amyloid precursor protein (APP) to amyloid beta peptide (A-beta) and following formation of amyloid plaques are the key events of Alzheimer’s pathology. Thus changes in APP expression and metabolism can lead to pathology development. Here we show that overexpression of human APP in Drosophila neural cells manifests in different morphological abnormalities of Drosophila imago that can be observed immediately after fly eclosion. This observation can help to further understand APP molecular functions and its participation in different molecular pathways.展开更多
In the presented work, the possibility of direct synthesis of LDH(layered double hydroxide) on the AZ91 surface in the presence of a chelating agent(diethylenetriaminepentaacetic acid-DTPA) is reported. Conversion lay...In the presented work, the possibility of direct synthesis of LDH(layered double hydroxide) on the AZ91 surface in the presence of a chelating agent(diethylenetriaminepentaacetic acid-DTPA) is reported. Conversion layer of LDH nanocontainers were formed under ambient pressure conditions without carbonate addition in the electrolyte. The obtained LDH was characterized using experimental(SEM,XRD, TGA, XPS, Raman, etc.) and computational methods(thermodynamic calculation, modeling of possible LDH crystal structures). A comparison of three possible LDHs(LDH-OH,-NO_(3) and-CO_(3)) was performed. Based on the experimental results and crystal simulation approach, it was confirmed, that the mixed LDH-OH/CO_(3) is grown on the surface in the presence of DTPA pentasodium salt.展开更多
In this work, the evaluation of natural radioactivity and spontaneous fission rates was performed for 8 nuclides from the natural radioactive 238U, 235U and 232Th decay chains. For this purpose, three samples of struc...In this work, the evaluation of natural radioactivity and spontaneous fission rates was performed for 8 nuclides from the natural radioactive 238U, 235U and 232Th decay chains. For this purpose, three samples of structural materials of the neutrino detector, i.e. aluminum, titanium and glass were analyzed by gamma spectroscopy and by neutron activation analysis to quantify a specific radioactivity of the samples. According to the results of this investigation, glass and aluminum samples have maximum values of the mean uranium concentrations 7.3(7) × 10-4% and 3.1(6) × 10-5%, respectively, while the lowest value for mean concentration of the uranium was found in titanium samples to be 4.7(3) × 10-6%. Aluminum sample had maximum values of the mean thorium concentrations, 2.5(8) × 10-3%, while the lowest value for mean concentration of the thorium was found in titanium samples to be 6.2(3) × 10-7%.展开更多
This manuscript presents an application of calculation methods in neutron activation analysis (NAA) of a large crude oil sample. Monte-Carlo computer code was developed. The computer code calculates neutron cross sect...This manuscript presents an application of calculation methods in neutron activation analysis (NAA) of a large crude oil sample. Monte-Carlo computer code was developed. The computer code calculates neutron cross sections and neutron flux density distribution in the interior large sample. ENDF/B-VII.0 data files and ENSDF BNL-NCS-51655-01/02-Rev data files were used as nuclear databases in our computer code. HPGe planar detector efficiency registration technique and the software were developed for the absolute NAA technique of the large sample. The concentrations of Na, K, Ca, Sc, Cr, Fe, Co, Ni, Cu, Zn, Ga, As, Br, Sr, Zr, Mo, Ag, Sb, Cs, Ba, Ce, Nd, Sm, Eu, Tb, Dy, Ho, Tm, Yb, Lu, Hf, Ta, W, Pt, Au, Hg, Th and U in the crude oil samples of Eastern Siberia oilfield were determined using calculation and relative techniques in the concentration range from 10-9 to 0.5%.展开更多
Neutron activation analysis technique of the Gd2O2S:М scintillation ceramics was developed. The concentrations of 15 trace, minor and major elements (As, Ce, Co, Cr, Cs, Eu, Fe, La, Sc, Tb, Zn, Zr, Pr, Gd, Na) have b...Neutron activation analysis technique of the Gd2O2S:М scintillation ceramics was developed. The concentrations of 15 trace, minor and major elements (As, Ce, Co, Cr, Cs, Eu, Fe, La, Sc, Tb, Zn, Zr, Pr, Gd, Na) have been measured with the instrumental neutron activation analysis of the Gd2O2S:Pr sample. The concentrations range of the determined elements is from 3 × 10-8 to 2.0% in mass. The determination limit of the elements was calculated to be (0.6 - 1.3 × 10-8% in mass).展开更多
As a continuous search for the 'missing'α-decay of 239Cm, several irradiation experiments were done in July, 2005. The whole experimental procedure was similar as last year. To increase the yield of expected ...As a continuous search for the 'missing'α-decay of 239Cm, several irradiation experiments were done in July, 2005. The whole experimental procedure was similar as last year. To increase the yield of expected isotopes with intensive 12C beam, all of the irradiation have been done at night, and typical beam intensities varied between 0. 4-0.6 particleμA. Each irradiation lasted 4-6 h. The procedure of preparing展开更多
It is of special interest to search for those unknown α-emitters in the transuranium region which (i) are located along the path of α-decay chains that start in the superheavy element region, and (ii) establish a li...It is of special interest to search for those unknown α-emitters in the transuranium region which (i) are located along the path of α-decay chains that start in the superheavy element region, and (ii) establish a link to nuclides with known masses. The knowledge of all Qαvalues in an α-decay chain allows obtaining展开更多
The Gatchina discharge phenomenon holds significant promise as a laboratory model for simulating ball lightning.However,crucial aspects concerning the plasma components of the resulting afterglow remain unresolved.Not...The Gatchina discharge phenomenon holds significant promise as a laboratory model for simulating ball lightning.However,crucial aspects concerning the plasma components of the resulting afterglow remain unresolved.Notably,the measurement of the electron density,a critical parameter,has not been fully achieved thus far.In this study,microwave diagnostics and video recording were employed during a pulsed Gatchina discharge,along with synchronous measurement of discharge current and voltage.Distinct antennas were positioned at different heights to enable separate diagnosis of the discharge and the ensuing long-lived afterglow.The findings revealed that during the active phase of the Gatchina discharge,the plasma density was substantial enough to cause reflection of an electromagnetic wave with a frequency of 20 GHz from this highly conductive object.In the afterglow,the signal experienced only a moderate weakening of 10–20 percent,facilitating the determination of the time dependence of average electron density during the afterglow's passage between the two antennas.These measurements verified the unusually slow plasma decay in the afterglow of the Gatchina discharge,suggesting the potential significance of chemi-ionisation processes involving long-lived(metastable)particles.展开更多
This article presents a synopsis of the current data on the mechanisms of blood-brain barrier (BBB) alteration and autoimmune response in acute ischemic stroke. Most researchers confirm the relationship between the se...This article presents a synopsis of the current data on the mechanisms of blood-brain barrier (BBB) alteration and autoimmune response in acute ischemic stroke. Most researchers confirm the relationship between the severity of immunobiochemical changes and clinical outcome of acute ischemic stroke. Ischemic stroke is accompanied by aseptic inflammation, which alters the brain tissue and exposes the co-stimulatory molecules of the immune system and the neuronal antigens. To date, BBB is not considered the border between the immune system and central nervous system, and the local immune subsystems are found within and behind the BBB. BBB disruption contributes to the leakage of brain autoantigens and induction of secondary autoimmune response to neuronal antigens and long-term inflammation. Glymphatic system function is altered and jeopardized both in hemorrhagic and ischemic stroke types. The receptors of innate immunity (toll-like receptor-2 and toll-like receptor-4) are also involved in acute ischemia-reperfusion injury. Immune response is related to the key processes of blood clotting and fibrinolysis. At the same time, the stroke-induced immune activation may promote reparation phenomena in the brain. Subsequent research on the reduction of the acute ischemic brain injury through the target regulation of the immune response is promising.展开更多
We reveal and explain the scaling behavior of the thermopower S/T exhibited by the archetypal heavy-fermion (HF) metal YbRh2Si2 under the application of magnetic field B at temperature T. We show that the same scali...We reveal and explain the scaling behavior of the thermopower S/T exhibited by the archetypal heavy-fermion (HF) metal YbRh2Si2 under the application of magnetic field B at temperature T. We show that the same scaling is demonstrated by different HF compounds such as/3-YbA1B4 and the strongly correlated layered cobalt oxide [BiBa0.66K0.3602]CoO2. Using YbRh2Si2 as an example, we demonstrate that the scaling behavior of SIT is violated at the antiferromagnetic phase transition, while both the residual resistivity Po and the density of states, N, experience jumps at the phase transition, causing the thermopower to make two jumps and change its sign. Our elucidation is based on flattening of the single-particle spectrum that profoundly affects Po and N. To depict the main features of the SIT behavior, we construct a T-B schematic phase diagram of YbRh2Si2. Our calculated SIT for the HF compounds are in good agreement with experimental facts and support our observations.展开更多
If the number of colors N c is taken large,baryons and their excitations can be considered in a mean-field approach.We argue that the mean field in baryons breaks spontaneously the spherical and SU(3) flavor symmetr...If the number of colors N c is taken large,baryons and their excitations can be considered in a mean-field approach.We argue that the mean field in baryons breaks spontaneously the spherical and SU(3) flavor symmetries,but retains the SU(2) symmetry of simultaneous rotations in space and isospace.The one-quark and quark-hole excitations in the mean field,together with the SU(3) rotational bands about them determine the spectrum of baryon resonances,which turns out to be in good accordance with reality when one puts N c =3.A by-product of this scheme is a confirmation of the light pentaquark Θ + baryon uudds as a typical Gamov–Teller resonance long known in nuclear physics.An extension of the same large-N c logic to charmed baryons leads to a prediction of a anti-decapenta (15)-plet of charmed pentaquarks,two of which,B ++ c = cuuds and B + c = cudds,may be light and stable with respect to strong decays.展开更多
A parity nonconserving (PNC) asymmetry in the cross section for dielectronic recombination of polarized electrons on multiply charged ions with Z≥40 is discussed. This effect is strongly enhanced for close doubly-exc...A parity nonconserving (PNC) asymmetry in the cross section for dielectronic recombination of polarized electrons on multiply charged ions with Z≥40 is discussed. This effect is strongly enhanced for close doubly-excited states of opposite parity in the intermediate compound ion. Such states are known for He-like ions.However, these levels have large energy and large radiative widths which hampers observation of the PNC asymmetry. We argue that accidentally degenerate states of more complex ions may be more suitable for the corresponding experiment.展开更多
The aim of this review paper is to expose a new state of matter exhibited by strongly correlated Fermi systems represented by various heavy-fermion (HF) metals, two-dimensional liquids like 3He, compounds with quant...The aim of this review paper is to expose a new state of matter exhibited by strongly correlated Fermi systems represented by various heavy-fermion (HF) metals, two-dimensional liquids like 3He, compounds with quantum spin liquids, quasicrystals, and systems with one-dimensional quantum spin liquid. We name these various systems HF compounds, since they exhibit the behavior typical of HF metals. In HF compounds at zero temperature the unique phase transition, dubbed throughout as the fermion condensation quantum phase transition (FCQPT) can occur; this FCQPT creates flat bands which in turn lead to the specific state, known as the fermion condensate. Unlimited increase of the effective mass of quasiparticles signifies FCQPT; these quasiparticles determine the thermodynamic, transport and relaxation properties of HF compounds. Our discussion of numerous salient experimen- tal data within the framework of FCQPT resolves the mystery of the new state of matter. Thus, FCQPT and the fermion condensation can be considered as the universal reason for the non-Fermi liquid behavior observed in various HF compounds. We show analytically and using arguments based completely on the experimental grounds that these systems exhibit universal scaling behavior of their thermodynamic, transport and relaxation properties. Therefore, the quantum physics of different HF compounds is universal, and emerges regardless of the microscopic structure of the compounds. This uniform behavior allows us to view it as the main characteristic of a new state of matter exhibited by HF compounds.展开更多
The present status of the Bonn-Gatchina partial wave analysis of the photoproduction and pion induced data is presented. An observation of signals which can be associated with new baryon resonances and possible interp...The present status of the Bonn-Gatchina partial wave analysis of the photoproduction and pion induced data is presented. An observation of signals which can be associated with new baryon resonances and possible interpretations of the baryon spectrum is discussed.展开更多
High resolution studies of ao/fo(980) decays into channels involving open strangeness are currently being performed at COSY-Julich. As a "filter" for isospin-zero intermediate states, i.e. to selectively produce t...High resolution studies of ao/fo(980) decays into channels involving open strangeness are currently being performed at COSY-Julich. As a "filter" for isospin-zero intermediate states, i.e. to selectively produce the f0(980) resonance, the dd →αK^+K^-reaction was measured with the magnetic ANKE spectrometer. In order to determine the luminosity of this experiment, the elastically and quasi-elastically scattered deuterons were recorded simultaneously with the αK^+K^- events. Here we report about the luminosity determination via investigating the (quasi-) elastic deuterons at ANKE.展开更多
We study coherent spin transport through helical edge states of topological insulator tunnel-coupled to metallic leads.We demonstrate that unpolarized incoming electron beam acquires finite polarization after transmis...We study coherent spin transport through helical edge states of topological insulator tunnel-coupled to metallic leads.We demonstrate that unpolarized incoming electron beam acquires finite polarization after transmission through such a setup provided that edges contain at least one magnetic impurity.The finite polarization appears even in the fully classical regime and is therefore robust to dephasing.There is also a quantum magnetic field-tunable contribution to the polarization,which shows sharp identical Aharonov-Bohm resonances as a function of magnetic flux—with the period hc/2e—and survives at relatively high temperature.We demonstrate that this tunneling interferometer can be described in terms of ensemble of flux-tunable qubits giving equal contributions to conductance and spin polarization.The number of active qubits participating in the charge and spin transport is given by the ratio of the temperature and the level spacing.The interferometer can effectively operate at high temperature and can be used for quantum calculations.In particular,the ensemble of qubits can be described by a single Hadamard operator.The obtained results open wide avenue for applications in the area of quantum computing.展开更多
The product of the ∧0/b (-B/0) differential production cross-section and the branching fraction of the decay ∧0/b→ J/ψ pK-(-B/0→ J/ψ-K*(892)0)is measured as a function of the beauty hadron transverse mome...The product of the ∧0/b (-B/0) differential production cross-section and the branching fraction of the decay ∧0/b→ J/ψ pK-(-B/0→ J/ψ-K*(892)0)is measured as a function of the beauty hadron transverse momentum, PT, and rapidity, y. The kinematic region of the measurements is pT〈20 GeV/c and 2.0 〈g〈4.5.The measurements use a data sample corresponding to an integrated luminosity of 3fb-1 collected by the LHCb detector in pp collisions at centre-of-mass energies √s=7 TeV in 2011 and √s=8 TeV in 2012. Based on previous LHCb results of the fragmentation fraction ratio,f∧0/b/fd,the branching fraction of the decay ∧0/b→ J/ψ pK-is measured to be B(∧0/b→ J/ψ pK-)=(3.17±0.04±0.07±0.34+0.45/-0.28)×10-4,where the first uncertainty is statistical, the second is systematic, the third is due to the uncertainty on the branching fraction of the decay -B/0 →J/ψ-K*(892)0,and the fourth is due to the knowledge of f∧0/b/fd.The sum of the asymmetries in the production and decay between ∧0/b and ∧0/bis also measured as a function of PT and y.The previously published branching fraction of ∧0/b→ J/ψ pπ-,relative to that of ∧0/b→ J/ψ pK-,is updated. The branching fractions of ∧0/b→P+c(→ J/ψp)K-are determined.展开更多
A search for the doubly charmed baryon ■^+cc is performed through its decay to theΛ^+c K^-π^+ final state,using proton-proton collision data collected with the LHCb detector at centre-of-mass energies of 7,8 and 13...A search for the doubly charmed baryon ■^+cc is performed through its decay to theΛ^+c K^-π^+ final state,using proton-proton collision data collected with the LHCb detector at centre-of-mass energies of 7,8 and 13 TeV.The data correspond to a total integrated luminosity of 9 fb^-1.No significant signal is observed in the mass range from 3.4 to 3.8 GeV/c^2.Upper limits are set at 95%credibility level on the ratio of the ■^+cc production cross-section times the branching fraction to that ofΛ^+c and ■^++cc baryons.The limits are determined as functions of the ■^+cc mass for different lifetime hypotheses,in the rapidity range from 2.0 to 4.5 and the transverse momentum range from 4 to 15 GeV/c.展开更多
The production of ■baryons in proton-proton collisions at a centre-of-mass energy of √s = 13 TeV is measured in the transverse-momentum range 4<pT<15GeV/c and the rapidity range2.0<y<4.5.The data used in...The production of ■baryons in proton-proton collisions at a centre-of-mass energy of √s = 13 TeV is measured in the transverse-momentum range 4<pT<15GeV/c and the rapidity range2.0<y<4.5.The data used in this measurement correspond to an integrated luminosity of 1.7fb^-1,recorded by the LHCb experiment during 2016.The ratio of the ■ production cross-section times the branching fraction of the■→∧^+cK^-π^+ π^+decay relative to the prompt ∧^+c production cross-section is found to be(2.22±0.27±0.29)×10^-4,assuming the central value of the measured lifetime,where the first uncertainty is statistical and the second systematic.展开更多
文摘Alzheimer’s disease (AD) is the leading and one of the most severe forms of dementia. Molecular mechanisms underlying AD pathogenesis despite much work on this subject still remain unclear. Cleavage of amyloid precursor protein (APP) to amyloid beta peptide (A-beta) and following formation of amyloid plaques are the key events of Alzheimer’s pathology. Thus changes in APP expression and metabolism can lead to pathology development. Here we show that overexpression of human APP in Drosophila neural cells manifests in different morphological abnormalities of Drosophila imago that can be observed immediately after fly eclosion. This observation can help to further understand APP molecular functions and its participation in different molecular pathways.
基金financial support of the I2B fund(Helmholtz Association)in frame of MUFfin project as well as ACTICOAT project in frame of Erafinancial support within the project CICECO-Aveiro Institute of Materials(UIDB/50011/2020&UIDP/50011/2020)financed by national funds through the FCT/MCTES and when appropriate co-financed by FEDER under the PT2020 Partnership Agreement。
文摘In the presented work, the possibility of direct synthesis of LDH(layered double hydroxide) on the AZ91 surface in the presence of a chelating agent(diethylenetriaminepentaacetic acid-DTPA) is reported. Conversion layer of LDH nanocontainers were formed under ambient pressure conditions without carbonate addition in the electrolyte. The obtained LDH was characterized using experimental(SEM,XRD, TGA, XPS, Raman, etc.) and computational methods(thermodynamic calculation, modeling of possible LDH crystal structures). A comparison of three possible LDHs(LDH-OH,-NO_(3) and-CO_(3)) was performed. Based on the experimental results and crystal simulation approach, it was confirmed, that the mixed LDH-OH/CO_(3) is grown on the surface in the presence of DTPA pentasodium salt.
文摘In this work, the evaluation of natural radioactivity and spontaneous fission rates was performed for 8 nuclides from the natural radioactive 238U, 235U and 232Th decay chains. For this purpose, three samples of structural materials of the neutrino detector, i.e. aluminum, titanium and glass were analyzed by gamma spectroscopy and by neutron activation analysis to quantify a specific radioactivity of the samples. According to the results of this investigation, glass and aluminum samples have maximum values of the mean uranium concentrations 7.3(7) × 10-4% and 3.1(6) × 10-5%, respectively, while the lowest value for mean concentration of the uranium was found in titanium samples to be 4.7(3) × 10-6%. Aluminum sample had maximum values of the mean thorium concentrations, 2.5(8) × 10-3%, while the lowest value for mean concentration of the thorium was found in titanium samples to be 6.2(3) × 10-7%.
文摘This manuscript presents an application of calculation methods in neutron activation analysis (NAA) of a large crude oil sample. Monte-Carlo computer code was developed. The computer code calculates neutron cross sections and neutron flux density distribution in the interior large sample. ENDF/B-VII.0 data files and ENSDF BNL-NCS-51655-01/02-Rev data files were used as nuclear databases in our computer code. HPGe planar detector efficiency registration technique and the software were developed for the absolute NAA technique of the large sample. The concentrations of Na, K, Ca, Sc, Cr, Fe, Co, Ni, Cu, Zn, Ga, As, Br, Sr, Zr, Mo, Ag, Sb, Cs, Ba, Ce, Nd, Sm, Eu, Tb, Dy, Ho, Tm, Yb, Lu, Hf, Ta, W, Pt, Au, Hg, Th and U in the crude oil samples of Eastern Siberia oilfield were determined using calculation and relative techniques in the concentration range from 10-9 to 0.5%.
文摘Neutron activation analysis technique of the Gd2O2S:М scintillation ceramics was developed. The concentrations of 15 trace, minor and major elements (As, Ce, Co, Cr, Cs, Eu, Fe, La, Sc, Tb, Zn, Zr, Pr, Gd, Na) have been measured with the instrumental neutron activation analysis of the Gd2O2S:Pr sample. The concentrations range of the determined elements is from 3 × 10-8 to 2.0% in mass. The determination limit of the elements was calculated to be (0.6 - 1.3 × 10-8% in mass).
文摘As a continuous search for the 'missing'α-decay of 239Cm, several irradiation experiments were done in July, 2005. The whole experimental procedure was similar as last year. To increase the yield of expected isotopes with intensive 12C beam, all of the irradiation have been done at night, and typical beam intensities varied between 0. 4-0.6 particleμA. Each irradiation lasted 4-6 h. The procedure of preparing
文摘It is of special interest to search for those unknown α-emitters in the transuranium region which (i) are located along the path of α-decay chains that start in the superheavy element region, and (ii) establish a link to nuclides with known masses. The knowledge of all Qαvalues in an α-decay chain allows obtaining
基金National Natural Science Foundation of China,Grant/Award Numbers:12175050,12205067Fundamental Research Funds for the Central Universities,Grant/Award Number:HIT.OCEF.2022036。
文摘The Gatchina discharge phenomenon holds significant promise as a laboratory model for simulating ball lightning.However,crucial aspects concerning the plasma components of the resulting afterglow remain unresolved.Notably,the measurement of the electron density,a critical parameter,has not been fully achieved thus far.In this study,microwave diagnostics and video recording were employed during a pulsed Gatchina discharge,along with synchronous measurement of discharge current and voltage.Distinct antennas were positioned at different heights to enable separate diagnosis of the discharge and the ensuing long-lived afterglow.The findings revealed that during the active phase of the Gatchina discharge,the plasma density was substantial enough to cause reflection of an electromagnetic wave with a frequency of 20 GHz from this highly conductive object.In the afterglow,the signal experienced only a moderate weakening of 10–20 percent,facilitating the determination of the time dependence of average electron density during the afterglow's passage between the two antennas.These measurements verified the unusually slow plasma decay in the afterglow of the Gatchina discharge,suggesting the potential significance of chemi-ionisation processes involving long-lived(metastable)particles.
文摘This article presents a synopsis of the current data on the mechanisms of blood-brain barrier (BBB) alteration and autoimmune response in acute ischemic stroke. Most researchers confirm the relationship between the severity of immunobiochemical changes and clinical outcome of acute ischemic stroke. Ischemic stroke is accompanied by aseptic inflammation, which alters the brain tissue and exposes the co-stimulatory molecules of the immune system and the neuronal antigens. To date, BBB is not considered the border between the immune system and central nervous system, and the local immune subsystems are found within and behind the BBB. BBB disruption contributes to the leakage of brain autoantigens and induction of secondary autoimmune response to neuronal antigens and long-term inflammation. Glymphatic system function is altered and jeopardized both in hemorrhagic and ischemic stroke types. The receptors of innate immunity (toll-like receptor-2 and toll-like receptor-4) are also involved in acute ischemia-reperfusion injury. Immune response is related to the key processes of blood clotting and fibrinolysis. At the same time, the stroke-induced immune activation may promote reparation phenomena in the brain. Subsequent research on the reduction of the acute ischemic brain injury through the target regulation of the immune response is promising.
文摘We reveal and explain the scaling behavior of the thermopower S/T exhibited by the archetypal heavy-fermion (HF) metal YbRh2Si2 under the application of magnetic field B at temperature T. We show that the same scaling is demonstrated by different HF compounds such as/3-YbA1B4 and the strongly correlated layered cobalt oxide [BiBa0.66K0.3602]CoO2. Using YbRh2Si2 as an example, we demonstrate that the scaling behavior of SIT is violated at the antiferromagnetic phase transition, while both the residual resistivity Po and the density of states, N, experience jumps at the phase transition, causing the thermopower to make two jumps and change its sign. Our elucidation is based on flattening of the single-particle spectrum that profoundly affects Po and N. To depict the main features of the SIT behavior, we construct a T-B schematic phase diagram of YbRh2Si2. Our calculated SIT for the HF compounds are in good agreement with experimental facts and support our observations.
基金Supported by Russian Government grant RFBR-09-02-01198Mercator Fellowship,DFG,Germany
文摘If the number of colors N c is taken large,baryons and their excitations can be considered in a mean-field approach.We argue that the mean field in baryons breaks spontaneously the spherical and SU(3) flavor symmetries,but retains the SU(2) symmetry of simultaneous rotations in space and isospace.The one-quark and quark-hole excitations in the mean field,together with the SU(3) rotational bands about them determine the spectrum of baryon resonances,which turns out to be in good accordance with reality when one puts N c =3.A by-product of this scheme is a confirmation of the light pentaquark Θ + baryon uudds as a typical Gamov–Teller resonance long known in nuclear physics.An extension of the same large-N c logic to charmed baryons leads to a prediction of a anti-decapenta (15)-plet of charmed pentaquarks,two of which,B ++ c = cuuds and B + c = cudds,may be light and stable with respect to strong decays.
文摘A parity nonconserving (PNC) asymmetry in the cross section for dielectronic recombination of polarized electrons on multiply charged ions with Z≥40 is discussed. This effect is strongly enhanced for close doubly-excited states of opposite parity in the intermediate compound ion. Such states are known for He-like ions.However, these levels have large energy and large radiative widths which hampers observation of the PNC asymmetry. We argue that accidentally degenerate states of more complex ions may be more suitable for the corresponding experiment.
基金Acknowledgements V.R. Shaginyan is supported by the Russian Science Foundation, Grant No. 14-22-00281. A. Z. Msezane thanks the US DOE, Division of Chemical Sciences, Office of Energy Research, and ARO for research support. K. G. Popov is partly supported by RFBR # 14-02-00044. V. A. Khodel thanks the McDonnell Center for the Space Sciences for support.
文摘The aim of this review paper is to expose a new state of matter exhibited by strongly correlated Fermi systems represented by various heavy-fermion (HF) metals, two-dimensional liquids like 3He, compounds with quantum spin liquids, quasicrystals, and systems with one-dimensional quantum spin liquid. We name these various systems HF compounds, since they exhibit the behavior typical of HF metals. In HF compounds at zero temperature the unique phase transition, dubbed throughout as the fermion condensation quantum phase transition (FCQPT) can occur; this FCQPT creates flat bands which in turn lead to the specific state, known as the fermion condensate. Unlimited increase of the effective mass of quasiparticles signifies FCQPT; these quasiparticles determine the thermodynamic, transport and relaxation properties of HF compounds. Our discussion of numerous salient experimen- tal data within the framework of FCQPT resolves the mystery of the new state of matter. Thus, FCQPT and the fermion condensation can be considered as the universal reason for the non-Fermi liquid behavior observed in various HF compounds. We show analytically and using arguments based completely on the experimental grounds that these systems exhibit universal scaling behavior of their thermodynamic, transport and relaxation properties. Therefore, the quantum physics of different HF compounds is universal, and emerges regardless of the microscopic structure of the compounds. This uniform behavior allows us to view it as the main characteristic of a new state of matter exhibited by HF compounds.
文摘The present status of the Bonn-Gatchina partial wave analysis of the photoproduction and pion induced data is presented. An observation of signals which can be associated with new baryon resonances and possible interpretations of the baryon spectrum is discussed.
基金Supported by Deutscher Akademischer Austausch Dienst
文摘High resolution studies of ao/fo(980) decays into channels involving open strangeness are currently being performed at COSY-Julich. As a "filter" for isospin-zero intermediate states, i.e. to selectively produce the f0(980) resonance, the dd →αK^+K^-reaction was measured with the magnetic ANKE spectrometer. In order to determine the luminosity of this experiment, the elastically and quasi-elastically scattered deuterons were recorded simultaneously with the αK^+K^- events. Here we report about the luminosity determination via investigating the (quasi-) elastic deuterons at ANKE.
基金The work was supported by the Russian Science Foundation(Grant No.20-12-00147)by the Foundation for the Advancement of Theoretical Physics and Mathematics"BASIS”.
文摘We study coherent spin transport through helical edge states of topological insulator tunnel-coupled to metallic leads.We demonstrate that unpolarized incoming electron beam acquires finite polarization after transmission through such a setup provided that edges contain at least one magnetic impurity.The finite polarization appears even in the fully classical regime and is therefore robust to dephasing.There is also a quantum magnetic field-tunable contribution to the polarization,which shows sharp identical Aharonov-Bohm resonances as a function of magnetic flux—with the period hc/2e—and survives at relatively high temperature.We demonstrate that this tunneling interferometer can be described in terms of ensemble of flux-tunable qubits giving equal contributions to conductance and spin polarization.The number of active qubits participating in the charge and spin transport is given by the ratio of the temperature and the level spacing.The interferometer can effectively operate at high temperature and can be used for quantum calculations.In particular,the ensemble of qubits can be described by a single Hadamard operator.The obtained results open wide avenue for applications in the area of quantum computing.
基金Supported by CERN and national agencies:CAPES,CNPq,FAPERJ and FINEP(Brazil)NSFC(China)+17 种基金CNRS/IN2P3(France)BMBF,DFG,HGF and MPG(Germany)INFN(Italy)FOM and NWO(The Netherlands)MNi SW and NCN(Poland)MEN/IFA(Romania)Min ES and FANO(Russia)Min ECo(Spain)SNSF and SER(Switzerland)NASU(Ukraine)STFC(United Kingdom)NSF(USA)supported by IN2P3(France),KIT and BMBF(Germany),INFN(Italy),NWOSURF(The Netherlands),PIC(Spain),Grid PP(United Kingdom)support from EPLANET,Marie Sk lodowska-Curie ActionsERC(European Union),Conseil général de Haute-Savoie,Labex ENIGMASS and OCEVU,RégionAuvergne(France),RFBR(Russia),Xunta GalGENCAT(Spain),Royal Society and Royal Commission for the Exhibition of 1851(United Kingdom)
文摘The product of the ∧0/b (-B/0) differential production cross-section and the branching fraction of the decay ∧0/b→ J/ψ pK-(-B/0→ J/ψ-K*(892)0)is measured as a function of the beauty hadron transverse momentum, PT, and rapidity, y. The kinematic region of the measurements is pT〈20 GeV/c and 2.0 〈g〈4.5.The measurements use a data sample corresponding to an integrated luminosity of 3fb-1 collected by the LHCb detector in pp collisions at centre-of-mass energies √s=7 TeV in 2011 and √s=8 TeV in 2012. Based on previous LHCb results of the fragmentation fraction ratio,f∧0/b/fd,the branching fraction of the decay ∧0/b→ J/ψ pK-is measured to be B(∧0/b→ J/ψ pK-)=(3.17±0.04±0.07±0.34+0.45/-0.28)×10-4,where the first uncertainty is statistical, the second is systematic, the third is due to the uncertainty on the branching fraction of the decay -B/0 →J/ψ-K*(892)0,and the fourth is due to the knowledge of f∧0/b/fd.The sum of the asymmetries in the production and decay between ∧0/b and ∧0/bis also measured as a function of PT and y.The previously published branching fraction of ∧0/b→ J/ψ pπ-,relative to that of ∧0/b→ J/ψ pK-,is updated. The branching fractions of ∧0/b→P+c(→ J/ψp)K-are determined.
基金support from CERN and from the national agencies:CAPES,CNPq,FAPERJ and FINEP(Brazil)MOST and NSFC(China)+11 种基金CNRS/IN2P3(France)BMBF,DFG and MPG(Germany)INFN(Italy)KWO(Netherlands)MNiSW and NCN(Poland)MEN/IFA(Romania)MinES and FASO(Russia)MinECo(Spain)SNSF and SER(Switzerland)NASU(Ukraine)STFC(United Kingdom)NSF(USA).
文摘A search for the doubly charmed baryon ■^+cc is performed through its decay to theΛ^+c K^-π^+ final state,using proton-proton collision data collected with the LHCb detector at centre-of-mass energies of 7,8 and 13 TeV.The data correspond to a total integrated luminosity of 9 fb^-1.No significant signal is observed in the mass range from 3.4 to 3.8 GeV/c^2.Upper limits are set at 95%credibility level on the ratio of the ■^+cc production cross-section times the branching fraction to that ofΛ^+c and ■^++cc baryons.The limits are determined as functions of the ■^+cc mass for different lifetime hypotheses,in the rapidity range from 2.0 to 4.5 and the transverse momentum range from 4 to 15 GeV/c.
基金Supported by CERNnational agencies:CAPES+30 种基金CNPqFAPERJFINEP(Brazil)MOSTNSFC(China)CNRS/IN2P3(France)BMBFDFGMPG(Germany)INFN(Italy)NWO(Netherlands)MNiSWNCN(Poland)MEN/IFA(Romania)MSHE(Russia)MinECo(Spain)SNSFSER(Switzerland)NASU(Ukraine)STFC(United Kingdom)DOE NPNSF(USA)Key Research Program of Frontier Sciences of CAS,CAS PIFIthe Thousand Talents Program(China)RFBRRSFYandex LLC(Russia)GVAXuntaGalGENCAT(Spain)the Royal Society and the Leverhulme Trust(United Kingdom)
文摘The production of ■baryons in proton-proton collisions at a centre-of-mass energy of √s = 13 TeV is measured in the transverse-momentum range 4<pT<15GeV/c and the rapidity range2.0<y<4.5.The data used in this measurement correspond to an integrated luminosity of 1.7fb^-1,recorded by the LHCb experiment during 2016.The ratio of the ■ production cross-section times the branching fraction of the■→∧^+cK^-π^+ π^+decay relative to the prompt ∧^+c production cross-section is found to be(2.22±0.27±0.29)×10^-4,assuming the central value of the measured lifetime,where the first uncertainty is statistical and the second systematic.