S. V. Laptev

Publications (13)2.84 Total impact

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  Available from: Sergey Aleksandrovich Akimenko

  Article: Measurement of K^{-}_{e3} branching ratio

  V I Romanovsky, S. A. Akimenko, G. I. Britvich, K. V. Datsko, A. P. Filin, A V Inyakin, A. S. Konstantinov, I. Y. Korolkov, V. A. Khmelnikov, V. M. Leontiev, [......], V F Obraztsov, V A Polyakov, V. I. Shelikhov, O. G. Tchikilev, V A Uvarov, O P Yushchenko, V. N. Bolotov, V. A. Duk, S. V. Laptev, A. Yu. Polyarush
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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

  S. A. Akimenko, V. N. Bolotov, G. I. Britvich, K. V. Datsko, V. A. Duk, A. P. Filin, E. N. Gushchin, A. V. Inyakin, V. A. Khmelnikov, A. S. Konstantinov, [......], V. P. Novikov, V. F. Obraztsov, V. A. Polyakov, A. Yu. Polyarush, V. E. Postoev, V. I. Romanovsky, V. I. Shelikhov, O. G. Tchikilev, V. A. Uvarov, O. P. Yushchenko
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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
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  Available from: Sergey Aleksandrovich Akimenko

  Article: Observation of the radiative kaon decay K− → µ−π0γν

  O. G. Tchikilev, S. A. Akimenko, G. I. Britvich, K. V. Datsko, A. P. Filin, A. V. Inyakin, V. A. Khmelnikov, A. S. Konstantinov, I. Ya. Korolkov, V. M. Leontiev, [......], V. F. Obraztsov, V. A. Polyakov, V. I. Romanovsky, V. I. Shelikhov, V. A. Uvarov, O. P. Yushchenko, V. N. Bolotov, S. V. Laptev, V. A. Duk, A. Yu. Polyarush
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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
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  Available from: Sergey Aleksandrovich Akimenko

  Article: Experimental study of direct photon emission in K/it− → π−π0γ decay using ISTRA+ detector

  V. A. Uvarov, S. A. Akimenko, V. N. Bolotov, G. I. Britvich, K. V. Datsko, V. A. Duk, A. P. Filin, A. V. Inyakin, V. A. Khmelnikov, A. S. Konstantinov, [......], V. P. Novikov, V. F. Obraztsov, V. A. Polyakov, A. Yu. Polyarush, V. I. Romanovsky, V. M. Ronjin, V. I. Shelikhov, N. E. Smirnov, O. G. Tchikilev, O. P. Yushchenko
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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
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  Available from: Sergey Aleksandrovich Akimenko

  Article: Study of K- -> pi0 e nu gamma decay with ISTRA+ setup

  V. N. Bolotov, E. N. Guschin, V. A. Duk, S. V. Laptev, V. A. Lebedev, A. E. Mazurov, A. Yu. Polyarush, V. E. Postoev, S. A. Akimenko, G. I. Britvich, [......], V. A. Khmelnikov, V. M. Leontiev, V. P. Novikov, V F Obraztsov, V A Polyakov, V I Romanovsky, V. I. Shelikhov, O. G. Tchikilev, V A Uvarov, O P Yushchenko
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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;
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  Available from: Sergey Aleksandrovich Akimenko

  Article: Experimental study of direct photon emission in K- --> pi- pi0 gamma decay using ISTRA+ detector

  V A Uvarov, S. A. Akimenko, G. I. Britvich, K. V. Datsko, A. P. Filin, A V Inyakin, V. A. Khmelnikov, A. S. Konstantinov, V F Konstantinov, I. Y. Korolkov, [......], V I Romanovsky, V M Ronjin, V. I. Shelikhov, N E Smirnov, O. G. Tchikilev, O P Yushchenko, V. N. Bolotov, V. A. Duk, S. V. Laptev, A. Yu. Polyarush
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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;
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  Available from: Sergey Aleksandrovich Akimenko

  Article: High statistic measurement of the K- -> pi0 e- nu decay form-factors

  O P Yushchenko, S. A. Akimenko, G. I. Britvich, K. V. Datsko, A. P. Filin, A V Inyakin, A. S. Konstantinov, V F Konstantinov, I. Y. Korolkov, V. A. Khmelnikov, [......], V A Polyakov, V I Romanovsky, V M Ronjin, V. I. Shelikhov, N E Smirnov, O. G. Tchikilev, V A Uvarov, V. N. Bolotov, S. V. Laptev, A. Yu. Polyarush
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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;
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  Available from: Sergey Aleksandrovich Akimenko

  Article: High statistic study of the K- -> pi0 mu- nu decay

  O P Yushchenko, S. A. Akimenko, K S Belous, G. I. Britvich, I. G. Britvich, K. V. Datsko, A. P. Filin, A V Inyakin, A. S. Konstantinov, V F Konstantinov, [......], V I Romanovsky, V M Ronjin, V. I. Shelikhov, N E Smirnov, O. G. Tchikilev, V A Uvarov, V. N. Bolotov, S. V. Laptev, A. R. Pastsjak, A. Yu. Polyarush
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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;
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  Available from: Sergey Aleksandrovich Akimenko

  Article: High statistics study of the K- -> pi0 e- nu decay

  I. V. Ajinenko, S. A. Akimenko, K S Belous, G. I. Britvich, I. G. Britvich, K. V. Datsko, A. P. Filin, A V Inyakin, A. S. Konstantinov, V F Konstantinov, [......], N E Smirnov, A. A. Sokolov, O. G. Tchikilev, V A Uvarov, O P Yushchenko, V. N. Bolotov, S. V. Laptev, A. R. Pastsjak, A. Yu. Polyarush, R. Kh. Sirodeev
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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;
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  Available from: Sergey Aleksandrovich Akimenko

  Article: Study of the K− → μ−νπ0 decay

  I. V. Ajinenko, S. A. Akimenko, G. I. Britvich, I. G. Britvich, K. V. Datsko, A. P. Filin, A. V. Inyakin, A. S. Konstantinov, V. F. Konstantinov, I. Ya. Korolkov, [......], M. V. Vasiliev, E. V. Vlasov, V. I. Yakimchuk, O. P. Yushchenko, V. N. Bolotov, S. V. Laptev, V. A. Lebedev, A. R. Pastsjak, A. Yu. Polyarush, R. Kh. Sirodeev
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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

  I. V. Ajinenko, S. A. Akimenko, G. A. Akopdzhanov, K. S. Belous, G. I. Britvich, I. G. Britvich, A. P. Filin, V. N. Govorun, A. V. Inyakin, V. A. Khmelnikov, [......], O. G. Tchikilev, E. V. Vlasov, O. P. Yushchenko, V. N. Bolotov, S. V. Laptev, A. Yu. Polyarush, V. E. Postoev, S. V. Yashchenko, B. Zh. Zalikhanov, V. Z. Serdyuk
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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
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  Available from: Sergey Aleksandrovich Akimenko

  Article: Measurement of the Dalitz plot slope parameters for K- -> pi0 pi0 pi- decay using ISTRA+ detector

  I. V. Ajinenko, S. A. Akimenko, G. I. Britvich, K. V. Datsko, A. P. Filin, A V Inyakin, A. S. Konstantinov, V F Konstantinov, I. Y. Korolkov, V. M. Leontiev, [......], V. I. Shelikhov, N E Smirnov, O. G. Tchikilev, V A Uvarov, O P Yushchenko, V. N. Bolotov, S. V. Laptev, A. R. Pastsjak, A. Yu. Polyarush, R. Kh. Sirodeev
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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

  O.P. Yushchenko, S.A. Akimenko, G.I. Britvich, K.V. Datsko, A.P. Filin, A.V. Inyakin, A.S. Konstantinov, V.F. Konstantinov, I.Y. Korolkov, V.A. Khmelnikov, [......], V.A. Polyakov, V.I. Romanovsky, V.M. Ronjin, V.I. Shelikhov, N.E. Smirnov, O.G. Tchikilev, V.A. Uvarov, V.N. Bolotov, S.V. Laptev, A.Yu. Polyarush
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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.