Publications (16)2.84 Total impact
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Article: Search for Heavy Neutrino in K->mu nu_h(nu_h-> nu gamma) Decay at ISTRA+ Setup
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ABSTRACT: Heavy neutrino nu_h with m_h < 300MeV/c^2 can be effectively searched for in kaon decays. We put upper limits on mixing matrix element |U_mu_h}|^2 for radiatively decaying nu_h from K->mu nu_h (nu_h -> nu gamma) decay chain in the following parameter region: 30MeV/c^2 < m_h < 80MeV/c^2; 10^{-11}sec < tau_h < 10^{-9}sec. For the whole region |U_{mu h}|^2 < 5 x 10^{-5} for Majorana type of nu_h and | U_{\mu h}|^2 < 8 x 10^{-5} for the Dirac case.10/2011; -
Article: Extraction of Kaon Formfactors from K^- -> mu^- nu_mu gamma Decay at ISTRA+ Setup
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ABSTRACT: The radiative decay K->mu nu gamma has been studied at ISTRA+ setup in a new kinematical region. About 22K events of K^- -> mu^- nu_mu gamma have been observed. The sign and value of Fv-Fa have been measured for the first time. The result is Fv-Fa=0.21(4)(4).05/2010; -
Article: Measurement of K^{-}_{e3} branching ratio
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ABSTRACT: The branching fraction for the decay $K^{-} \to \pi^{0} e \bar \nu$ is measured using in-flight decays detected with {\bf ISTRA+} setup working at the 25 GeV negative secondary beam of the U-70 PS:\linebreak $Br_{K_{e3}}= (5.124 \pm 0.009 (stat) \pm 0.029(norm) \pm 0.030(syst))%$. From this value the $|V_{us}|$ element of the CKM matrix is extracted, using previously measured $f_{+}(t)$ form factor: $|V_{us}|=0.227 \pm 0.002$. The results are in agreement with recent measurements by BNL E865, FNAL KTeV, KLOE.05/2007; -
Article: Study of decay with ISTRA+ setup
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ABSTRACT: Results of study of the K- ® p0 e-[`(n)] gK^ - \to \pi ^0 e^ - \overline \nu \gamma decay at the ISTRA+ setup are presented. We observed 4476 events of this decay. The branching ratio is found to be R = \fracBr(K- ® p0 e-[`(n)] e g)Br(K- ® p0 e-[`(n)] e )R = \frac{{Br(K^ - \to \pi ^0 e^ - \overline \nu _e \gamma )}}{{Br(K^ - \to \pi ^0 e^ - \overline \nu _e )}} = (1.81±0.03(stat.)±0.07(syst.)) × 10−2 for E*γ > 10 MeV and θ*eγ > 10°. For comparison with the previous experiment the branching ratio with cuts E*γ > 10 MeV, 0.6 < cos θ*eγ < 0.9 is calculated: R = \fracBr(K- ® p0 e-[`(n)] e g)Br(K- ® p0 e-[`(n)] e )\frac{{Br(K^ - \to \pi ^0 e^ - \overline \nu _e \gamma )}}{{Br(K^ - \to \pi ^0 e^ - \overline \nu _e )}} = (0.47±0.02(stat.) ± 0.03(syst.)) × 10−2. For the cuts E*γ > 30 MeV and θ*eγ > 20°, used in most theoretical papers, Br = (3.06 ± 0.09(stat.) ± 0.14(syst.)) × 10−4. For the asymmetry we get A ξ = −0.015 ± 0.021. At present it is the best estimate of this asymmetry.Physics of Atomic Nuclei 03/2007; 70(4):702-708. · 0.57 Impact Factor -
Article: Observation of the radiative kaon decay K− → µ−π0γν
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ABSTRACT: Using data collected with the ISTRA+ spectrometer during the 2001 run of the U-70 proton synchrotron in Protvino, the first observation of the radiative kaon decay K − → µ−π0γν is reported. The ratio Br(K µ3γ, 5 < E*γ < 30 MeV)/Br(K µ3) is found to be [0.270 ± 0.029(stat.) ± 0.026(syst.)]% and the ratio Br(K µ3γ, 30 < E*γ < 60 MeV)/Br(K µ3) = [0.0448 ± 0.0068(stat.) ± 0.0099(syst.)]%. These ratios are consistent with the theoretical predictions 0.21 and 0.047%, respectively. The measured angular distribution asymmetry for the region 5 < E*γ < 30 MeV, A(cos ϑ*µγ) = 0.093 ± 0.141, is two standard deviations away from the theoretical prediction of 0.354. The measured asymmetry in the T-odd variable ξ = pγ · (pµ × pπ)/m K 3 is −0.03 ± 0.13.Physics of Atomic Nuclei 12/2006; 70(1):29-34. · 0.57 Impact Factor -
Article: Experimental study of direct photon emission in K/it− → π−π0γ decay using ISTRA+ detector
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ABSTRACT: The branching ratio in the charged-pion-kinetic-energy region of 55 to 90 MeV for the direct photon emission in the K − → π−π0γ decay has been measured using in-flight decays detected with the ISTRA+ setup operating in the 25-GeV/c negative secondary beam of the U-70 PS. The value Br(DE)=[0.37±0.39(stat.)±0.10(syst.)]×10−5 obtained from the analysis of 930 completely reconstructed events is consistent with the average value of two stopped-kaon experiments, but it differs by 2.5 standard deviations from the average value of three in-flight-kaon experiments. The result is also compared with recent theoretical predictions.Physics of Atomic Nuclei 12/2005; 69(1):26-34. · 0.57 Impact Factor -
Article: Study of K- -> pi0 e nu gamma decay with ISTRA+ setup
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ABSTRACT: Results of study of the radiative kaon decay K-->pi0 e nu gamma at ISTRA+ setup are presented. 4476 events of this decay have been observed. The branching ratio is measured.11/2005; -
Article: Experimental study of direct photon emission in K- --> pi- pi0 gamma decay using ISTRA+ detector
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ABSTRACT: The branching ratio in the charged-pion kinetic energy region of 55 to 90 MeV for the direct photon emission in the K- --> pi- pi0 gamma decay has been measured using in-flight decays detected with the ISTRA+ setup operating in the 25 GeV/c negative secondary beam of the U-70 PS. The value Br(DE)=[0.37+-0.39(stat)+-0.10(syst)]*10^(-5) obtained from the analysis of 930 completely reconstructed events is consistent with the average value of two stopped-kaon experiments, but it differs by 2.5 standard deviations from the average value of three in-flight-kaon experiments. The result is also compared with recent theoretical predictions.11/2004; -
Article: High statistic measurement of the K- -> pi0 e- nu decay form-factors
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ABSTRACT: The decay K- -> pi0 e- nu is studied using in-flight decays detected with the ISTRA+ spectrometer. About 920K events are collected for the analysis. The lambda+ slope parameter of the decay form-factor f+(t) in the linear approximation (average slope) is measured: lambda+(lin)= 0.02774 +- 0.00047(stat) +- 0.00032(syst). The quadratic contribution to the form-factor was estimated to be lambda'+ = 0.00084 +- 0.00027(stat) +- 0.00031(syst). The linear slope, which has a meaning of df+(t)/dt|_{t=0} for this fit, is lambda+ = 0.02324 +- 0.00152(stat) +- 0.00032(syst). The limits on possible tensor and scalar couplings are derived: f_{T}/f_{+}(0)=-0.012 +- 0.021(stat) +- 0.011$(syst), f_{S}/f_{+}(0)=-0.0037^{+0.0066}_{-0.0056}(stat) +- 0.0041(syst).05/2004; -
Article: High statistic study of the K- -> pi0 mu- nu decay
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ABSTRACT: The decay K- -> pi0 mu- nu has been studied using in-flight decays detected with the "ISTRA+" spectrometer. About 540K events were collected for the analysis. The lambda+ and lambda0 slope parameters of the decay form-factors f+(t), f0(t) have been measured : lambda+ = 0.0277+-0.0013 (stat)+-0.0009 (syst), lambda0 = 0.0183+-0.0011(stat)+-0.0006(syst), and d(lambda0)/d(lambda+)=-0.348. The limits on the possible tensor and scalar couplings have been derived: fT/f+(0)=-0.0007 +- 0.0071, fS/f+(0)=0.0017 +- 0.0014. No visible non-linearity in the form-factors have been observed.12/2003; -
Article: High statistics study of the K- -> pi0 e- nu decay
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ABSTRACT: The decay K- -> pi0 e- nu has been studied using in-flight decays detected with the "ISTRA+" spectrometer working at the 25 GeV negative secondary beam of the U-70 PS. About 550K events were used for the analysis. The lambda+ parameter of the vector form-factor has been measured: lambda+ = 0.0286 +- 0.0008 (stat) +- 0.0006(syst). The limits on the possible tensor and scalar couplings have been obtained: f(T)/f+(0)=0.021 +0.064 -0.075 (stat) +- 0.026(syst) ; f(S)/f+(0)=0.002 +0.020 -0.022 (stat) +- 0.003(syst)10/2003; -
Article: Study of the K− → μ−νπ0 decay
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ABSTRACT: The decay K − → μ − νπ 0 has been studied using in-flight decays detected with the ISTRA+ setup operating in the 25-GeV negative secondary beam of the U-70 PS. About 112K events were used for the analysis. The λ + and λ 0 slope parameters of the decay form factors f +(t) and f 0(t) have been measured: λ +=0.0321±0.004(stat.)±0.002(syst.), λ 0=0.0209±0.004(stat.)±0.002(syst.); the correlation dλ 0/dλ +=−0.46. The limits on the possible tensor and scalar couplings have been derived: f T/f +(0)=−0.021±0.028(stat.)±0.014(theor.), f S/f +(0)=0.004±0.005(stat.)±0.005(theor.).Physics of Atomic Nuclei 12/2002; 66(1):105-109. · 0.57 Impact Factor -
Article: Study of the K− → e−νπ0 decay
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ABSTRACT: The decay K − → e − νπ 0 has been studied using in-flight decays detected with the ISTRA+ setup working at the 25-GeV negative secondary beam of the U-70 PS. About 130K events were used for the analysis. The λ + parameter of the vector form factor has been measured: λ +=0.0293±0.0015(stat.)±0.002(syst.). The limits on the possible tensor and scalar couplings have been derived: f T/f +(0)=−0.045±0.060(stat.) and f S/f +(0)=−0.019 −0.016 +0.025 (stat.).Physics of Atomic Nuclei 10/2002; 65(11):2064-2069. · 0.57 Impact Factor -
Article: Measurement of the Dalitz plot slope parameters for K- -> pi0 pi0 pi- decay using ISTRA+ detector
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ABSTRACT: The Dalitz plot slope parameters g, h and k for the K- -> pi0 pi0 pi- decay have been measured using in-flight decays detected with the ISTRA+ setup operating in the 25 GeV negative secondary beam of the U-70 PS. About 252 K events with four-momenta measured for the pi- and four involved photons were used for the analysis. The values obtained g=0.627+/-0.004(stat)+/-0.010(syst), h=0.046+/-0.004(stat)+/-0.012(syst), k=0.001+/-0.001(stat)+/-0.002(syst) are consistent with the world averages dominated by K+ data, but have significantly smaller errors.06/2002; -
Article: High statistic measurement of the K−→π0e−ν decay form-factors
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ABSTRACT: The decay K−→π0e−ν is studied using in-flight decays detected with the “ISTRA+” spectrometer. About 920K events are collected for the analysis. The λ+ slope parameter of the decay form-factor f+(t) in the linear approximation (average slope) is measured: λ+lin=0.02774±0.00047(stat)±0.00032(syst). The quadratic contribution to the form-factor was estimated to be λ′+=0.00084±0.00027(stat)±0.00031(syst). The linear slope, which has a meaning of df+(t)/dt|t=0 for this fit, is λ+=0.02324±0.00152(stat)±0.00032(syst). The limits on possible tensor and scalar couplings are derived: fT/f+(0)=−0.012±0.021(stat)±0.011(syst), fS/f+(0)=−0.0037+0.0066−0.0056(stat)±0.0041(syst).Physics Letters B. -
Article: Extraction of kaon formfactors from K−→μ−νγ decay at ISTRA+ setup
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ABSTRACT: The radiative decay K−→μ−νμγ has been studied at ISTRA+ setup in a new kinematic region. About 22K events of K−→μ−νμγ have been observed. The sign and value of FV−FA have been measured for the first time. The result is FV−FA=0.21±0.04(stat)±0.04(syst).Physics Letters B. 695:59-66.
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Institutions
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2002–2006
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Institute of High Energy Physics
Protvino, Moskovskaya, Russia
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