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Veksler and Baldin Laboratory of High Energy Physics

Delta-Sigma experiment. The results obtained and Δσ T (np) measurements planned using new high intensity polarized deuteron beam at the Nuclotron-M. Veksler and Baldin Laboratory of High Energy Physics Joint Institute for Nuclear Research. Outline.

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Veksler and Baldin Laboratory of High Energy Physics

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  1. Delta-Sigma experiment. The results obtained and ΔσT (np) measurementsplanned using new high intensity polarized deuteron beam at the Nuclotron-M Veksler and Baldin Laboratory of High Energy Physics Joint Institute for Nuclear Research Delta-Sigma experimentt

  2. Outline • Introduction. Urgency of the data obtaining for np spin observables in the GeV region. Aim of the Delta-Sigma experiment. • Determination ofthe ΔσL,T(np), A00kk(np), A00nn(np) and Rdpobservables and research program of experiment. • Experimental set-up with instrumentation for transmission ΔσL,T(np)measurements and magnetic spectrometer for elastic nppn charge exchange events detection. • The resultsobtained in frame of Delta-Sigma experiment research program. • Coming ΔσT(np) measurementsat the Nuclotron-M. Delta-Sigma experimentt

  3. The aim of the project is to extend investigations ofNNinteraction over a new high energy region of free polarized neutron beams1.2 – 3.7 GeV provided at present only at the JINR VBLHEP. • The main task of these studies is determination for the first time the imaginary and real parts of allspin-dependent elasticnpforwardscattering amplitudes over this energy region. • To reach this aim, a complete data set on energy dependencies ofnp spin-dependent observables have to be obtained for direct and simple reconstruction of these amplitudes. Delta-Sigma experimentt

  4. At the forward (θCM = 0) and backward(θCM = π) angles five complex invariant amplitudesa, b, c, d, and efrom the invariant amplitudes representation, which are the functions of the angle θCM and energy ECM, satisfy the following equations: a(0) − b(0) = c(0) + d(0), e(0) = 0, (1) a(π) − b(π) = c(π) − d(π), e(π) = 0. (2) Therefore only three complex amplitudes are independentin these directions. The forward and backwardscattering amplitudes are connected by the angularsymmetry conditions. We assume that the I = 1amplitudes are known. Consequently for the directreconstruction of the npforward amplitudes, altogether, at least six independent npobservables at either the forward or backward directionsare needed. Delta-Sigma experimentt

  5. The Delta-Sigma research program foresees the measurements of total cross section differencesΔσL,T(np) and spin correlation parameters A00kk(np)and A00nn(np)atθCM= π for the longitudinal (L- along the incident nucleon momentumk) and transverse (T– along the perpendicularnto thek) beam and target polarization directions, respectively. Delta-Sigma experimentt

  6. Determination of ΔσL,T (np) Observables The general expression for the total cross section of a polarized nucleon beam trasmitted through a polarized proton target is (S.M.Bilenky and R.M.Ryndin, Phys.Lett. 6 (1963) 217, R.J.N. Phillips, Nucl.Phys. 43 (1963) 413): σtot = σ0tot + σ1tot (PB PT) + σ2tot (PB k)(PTk),(3) where PBand PTare the beam and target polarizations, and k is the unit vector in the incident beam direction. The term σ0tot is the spin-independent total cross section, and σ1totand σ2tot are the spin-dependent contributions which connect with the observables ΔσT and ΔσL by the relations: – ΔσT = 2 σ1tot = [σtot (↑↑) – σtot (↓↑)]/PB PT,(4) – ΔσL = 2 (σ1tot + σ2tot) = [σtot (→→) – σtot(→←)]/PB PT.(5) From isotopic invariance of strong interaction, one can write the following expressions for total cross section differences at isosinglet and isotriplet states: ΔσL,T (np) = ½ ΔσL,T (I=0) + ½ ΔσL,T (I=1),(6) ΔσL,T (pp) = ΔσL,T (nn) = ΔσL,T (I=1), (7) ΔσL,T (I=0) = 2 ΔσL,T (np) – ΔσL,T (pp). (8) Using the last equation, one can obtain values of ΔσL,T (I=0) from known quantities of ΔσL,T (np) and ΔσL,T (pp), measured at the same energy. Delta-Sigma experimentt

  7. Values ofσ0tot, ΔσTandΔσLare connected with the imaginary parts of three invariant forwardscattering amplitudesa + b, c anddvia three opticaltheorems: σ0tot = (2π/K) Im [a(0) + b(0)],(9) – ΔσT = (4π/K) Im [c(0) + d(0)],(10) – ΔσL= (4π/K) Im [c(0) – d(0)].(11) From measuredΔσL,T (np)values one can unambiguouslyextract imaginary parts of invariant forward scattering amplitudesc anddusingEq. (10,11). Delta-Sigma experimentt

  8. The A00kk(np)and A00nn(np) values are to be defined in the backward direction. These observables will be measured by registration ofyields of elastic charge exchange processnppn at θLab = 0. They could be measured simultaneously with the corresponding ΔσL,T(np) transmission experiments. Delta-Sigma experimentt

  9. Measurements of the spin-correlation parameters A00kk(np) and A00nn(np) from np→pn process at 0º in Lab If the scattered particles are detected at 0º angle then only two non- vanishing spin-dependent quantities A00nn(E,0º) and A00kk(E,0º) can be measured from the np→pn scattering. C.Lechanoine-Leluc and F.Lehar. Rev. Mod. Phys. 65, 47 (1993). J. Ball, R.Binz, J.Bystricky et al. Eur.Phys.J. C 5, 57 (1998). These np-observables are connected with the invariant amplitudes by (the centre of mass system): dσ/dΩ (π) = ½ [|a|2 + |b|2 + |c|2 + |d|2], (12) dσ/dΩ A00nn(π) = ½ [|a|2 – |b|2 – |c|2 + |d|2], (13) dσ/dΩ A00kk(π) = Re a* d + Re b* c. (14) These equations can be transformed to: dσ/dΩ (1 + A00kk) = |b + c|2 = A + (Re b + Re c)2, (15) dσ/dΩ (1 – A00kk – 2A00nn) = |b – c|2 = B + (Re b – Re c)2, (16) dσ/dΩ (1 – A00kk + 2A00nn) = |b + c – 2d|2 = = C + (Re b + Re c – 2Re d)2, (17) where terms A, B, C contain the amplitudes imaginary parts only. Delta-Sigma experimentt

  10. Using the known imaginary parts of the forward amplitudes transformed into the backward direction, the np differential cross section and the two spin correlation parameters A00kk(np)and A00nn(np)atθCM = π are sufficient to obtain the real parts of all the three amplitudes from Eqs.(15) − (17). Delta-Sigma experimentt

  11. But in contrast to the optical theorems at θCM = 0, the scattering amplitudes in the backward direction are related to the np scattering observables by bilinear equations. Each of them may have, in principle, an independent ambiguity in the sign. The total ambiguity is then eight-fold at most and any independent experiment decreases it by a factor of two. Delta-Sigma experimentt

  12. To reduce the total ambiguity in the scattering amplitude determination, the Delta-Sigma collaboration performed the measurements of the ratio Rdp = dσ/dΩ (nd→p(nn))/dσ/dΩ (np→pn). for the charge exchange processes on the deuterium and hydrogen targets. Delta-Sigma experimentt

  13. Experimental observable Rdp = dσ/dΩ(nd→p(nn )) / dσ/dΩ(np→pn)(18) is the ratio of a quasi-elastic ndscattering differential cross section to the free np elastic scattering one. At θCM = πF.Lehar. Phys. Part. Nucl. 40, No. 6 (2009) Rdp (π) = (2/3) · dσ/dΩSD (np) / dσ/dΩ(np),(19) Rdp (π) = (2/3) · [0.25 · |a - b|2 + 0.5 · ( |c|2 - |d|2 )] / 0.5 · ( |a|2 + |b|2 + |c|2 + |d|2 ),(20) where dσ/dΩSD (np)is the “spin-dependent” part of the np→pn differential cross section. The values of Rdp can give one additional relation between spin-dependent NN-amplitudes and a set of such data allows to avoid one uncertainty of extraction of amplitudes real parts. Energy dependence of the ratio Rdpfor elastic charge exchange process np→pn at 0ºin Lab (or elastic np→np backward scattering in C.M.S.) has been measured using high intensity unpolarised neutron beam from theNuclotron andthe magnetic spectrometer of the Delta-Sigma set-up with liquid hydrogen and deuterium targets. Delta-Sigma experimentt

  14. DELTA-SIGMA Setup at the Polarized Neutron Beams of the JINR VBLHE VP 1 – beam line of polarized deuterons; 1V– beam line of polarized neutrons; BT– beryllium neutron production target; IC– ionization chamber; PIC 1-3, 9-16 – multiwire proportional/ionization chambers; CM– sweeping magnet; C1-C4 – set of neutron beam collimators; SRM – neutron spin rotating magnet; PPT – polarized proton target; NP– neutron profilometer Delta-Sigma experimentt

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  16. Measurements of the −ΔσL(np)energy dependence were carried out at ten different values of the polarized neutron beam energy from 1.2 to 3.7 GeV. The L-polarized neutron beam at the Synchrophasotron facility of the JINR VBLHE and the Dubna L-polarized proton target were used. Delta-Sigma experimentt

  17. Energy Dependence of the –ΔσL (np) Observable Obtained with Free Neutron Polarized Beams Delta-Sigma experimentt

  18. Energy Dependence of the –ΔσL (I=0) Delta-Sigma experimentt

  19. Measurements of the −ΔσL (np)energy dependence were in the main completed. Results were published in: References on –ΔσL (np) results 1. B.P.Adiasevich, V.G.Antonenko, S.A.Averichev, L.S.Azhgirey et al. Zeitschrift fur Physik C71 (1996) 65. 2. V.I.Sharov, S.A.Zaporozhets, B.P.Adiasevich, V.G.Antonenko et al. JINR Rapid Communications 3[77]-96 (1996) 13. 3. V.I.Sharov, S.A.Zaporozhets, B.P.Adiasevich, N.G.Anischenko et al. JINR Rapid Communications 4[96]-99 (1999) 5. 4. V.I.Sharov, S.A.Zaporozhets, B.P.Adiasevich, N.G.Anischenko et al. European Physical Journal C13 (2000) 255. 5. V.I.Sharov, N.G.Anischenko, V.G.Antonenko, S.A.Averichev et al. European Physical Journal C37 (2004) 79-90. 6. V.I.Sharov, N.G.Anischenko, V.G.Antonenko, S.A.Averichev et al. Yadernaya Fizika v.68, №11 (2005) 1858-1873. Physics of Atomic Nuclei v.68, №11 (2005) 1796-1811. Delta-Sigma experimentt

  20. The magnetic spectrometer consist of the analyzing dipole SP94, two sets of multiwire proportional chambers PCs: Gx, Gy, 1x, 2x before and PCs: 3x, 3y, 4x, 4y after SP94 for momentum analyzis of detected secondaries; • Time-of flight system S1, TOF1,2 for particle identification; • Liquid H2 / D2 or solid CH2 / CD2 targets inserted in the neutron beam line instead of the PPT and surrounded by a device DTS for detecting charged recoils and gammas; • Trigger counters A, S1, ST1,2,3. Delta-Sigma experimentt

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  25. ЯДЕРНАЯ ФИЗИКА, 2009, том 72,№6, с. 1051–1064 ЭЛЕМЕНТАРНЫЕ ЧАСТИЦЫ И ПОЛЯ THE RATIO Rdp OF THE QUASI-ELASTIC nd→p(nn) TO THE ELASTIC np→pn CHARGE-EXCHANGE-PROCESS YIELDS AT THE PROTON EMITTING ANGLE θp,lab = 0◦ OVER 0.55–2.0-GeV NEUTRON BEAM ENERGY REGION. EXPERIMENTAL RESULTS V. I. Sharov1)*, A. A. Morozov1), R.A.Shindin1), V.G.Antonenko2), S. B. Borzakov3), Yu. T. Borzunov1), E. V. Chernykh1), V. F. Chumakov1), S.A.Dolgii1), M. Finger4), 5), M.Finger, Jr.4), L. B. Golovanov1), D. K. Guriev1), A. Janata4), A. D. Kirillov1), A. D. Kovalenko1), V.A.Krasnov1), N. A. Kuzmin6), A. K. Kurilkin1), P. K. Kurilkin1), A.N.Livanov1), V.M.Lutsenko6), P.K.Maniakov1), E. A. Matyushevsky1), G. P. Nikolaevsky1), A. A. Nomofilov1), Tz. Panteleev3), 7), S. M. Piyadin1), I. L. Pisarev4), Yu. P. Polunin 2), A. N. Prokofiev8), V.Yu.Prytkov1), P.A.Rukoyatkin1), M. Slunecˇ ka4), 5), V.Slunecˇ kova. 4), A.Yu.Starikov1), L.N.Strunov1), T. A. Vasiliev1), E. I. Vorobiev1), I.P.Yudin6), I.V.Zaitsev1), A. A. Zhdanov8), V.N.Zhmyrov4) Received May 20, 2008; in final form, December 29, 2008 Physics of Atomic Nuclei, 2009, Vol. 72, No. 6, pp. 1007–1020. ELEMENTARY PARTICLES AND FIELDS Experiment Delta-Sigma experimentt

  26. ЯДЕРНАЯ ФИЗИКА, 2009, том 72,№6, с. 1065–1069 ЭЛЕМЕНТАРНЫЕ ЧАСТИЦЫ И ПОЛЯ THE RATIO Rdp OF THE QUASI-ELASTIC nd→p(nn) TO THE ELASTIC np→pn CHARGE-EXCHANGE-PROCESS YIELDS AT THE PROTON EMITTING ANGLE θp,lab = 0◦ OVER 0.55–2.0-GeV NEUTRON-BEAM ENERGY REGION. COMPARISON OF THE RESULTS WITH THE MODEL-DEPENDENT CALCULATIONS V. I. Sharov*, A. A. Morozov, R. A. Shindin, E. V. Chernykh, A. A. Nomofilov, L. N. Strunov Joint Institute for Nuclear Research, Dubna, Russia Received May 20, 2008; in final form, October 4, 2008 Physics of Atomic Nuclei, 2009, Vol. 72, No. 6, pp. 1021–1025. ELEMENTARY PARTICLES AND FIELDS Experiment Delta-Sigma experimentt

  27. The project status R E P O R T ON SCIENTIFIC PROJECT AND PROPOSAL FOR PROLONGATION OF THESE INVESTIGATIONS FOR 2010–2012 UNDER NEW PROJECT Delta-Sigma-T (proposal) Delta-Sigma experimentt

  28. THE COMING RESEARCH PROGRAM The coming research program under the project on 2010–2012 is following: Using adequate T-polarized neutron beam and T-polarized proton target to perform • the measurements of the ΔσT (np) at the same energy points (1.2 – 3.7 GeV) as for ΔσL (np) with energy steps of 100–200 MeV and expected statistical errors ≤ 0.5 mb; • the measurements of the energy dependencies of spin-correlation parameter A00nn (np) at the same energy points as for ΔσT (np) with expected statistical errors 0.02–0.05. These measurements will be performed simultaneously with and independently of the ΔσT (np) ones. Delta-Sigma experimentt

  29. Measurements of the ΔσT (np)and A00nn(np) energy dependences using T orientations of beam and target polarizations will be possible in the near future when the new high intensity source of polarized deuterons SPD will be put in operation at the Nuclotron-Mand when the Tmode of target polarization will be ready. Delta-Sigma experimentt

  30. Sidorin talk, April 16, 2009. Nuclotron_M status and nearest plans. Development and creation of a high-intensity polarized deuteron source (V.Fimushkin) We continue collaboration works with INR (Troitsk) on the development of the new high-intensity polarized deuteron source, and signed an addendum for work prolongation in 2009. We plan to complete TDR documentation in this year and start construction of some elements at INR. Simulation, modeling and design of different elements of the future source is in active phase at LHEP. Experimental hall for the future test bench with that source is prepared at LHEP building 203A, preparation electrical and water-cooling works were performed. It is purchased part of necessary vacuum equipment (turbomolecular pumps) for the SPD realization in 2009 – delivery in August 2009. SPD putting into operation: the end of 2010. Delta-Sigma experimentt

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  34. If intensity of the polarized deuteron beam will be 2х1010d/cycle then: at the neutron beam energy Tn = 1.2 GeV during 8hours will be accumulated a statistics provides the −∆σT(np) statistical error of ≈ 0.1 mb. The A00nn(np), measured simultaneously with and independently of the ΔσL,T(np) measurements, will has less then 0.05 statistical error. Delta-Sigma experimentt

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  36. FURTHER DESIRED MEASUREMENTS • Using suitable L-polarized neutron beam and L-polarized proton target to perform - the more precise and detailed measurements of the ΔσL (np) near Tn=1.8 GeV at 2–3 energy points with energy steps of 100 MeV and expected statistical errors lessthan0.5 mb; - the measurements of the energy dependencies of spin- correlation parameters A00kk (np) at the same energy points as for ΔσL (np) with expected statistical errors 0.02–0.05. These measurements can be performed independently of the ΔσL (np) ones. • Using a high intensity unpolarized deuteron beam for preparing free neutron beam and liquid hydrogen and deuterium targets to continue the measurements of ratio Rdp=dσ/dΩ(nd) / dσ/dΩ(np) for elastic charge- exchange process np→pn at 0° angle with 5% statistical errors at the energies more then 2.0 GeV. Delta-Sigma experimentt

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  39. The investigations under the project program were in part supported by the International Science Foundation and Russian Government, Grant N JHW 100, the Russian Foundation for Basic Research, Grants N 96-02-18736, N 02-02-17129, N 07-02-01025. Delta-Sigma experimentt

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  43. Participants of the "DELTA-SIGMA" experiment S.A.Averichev, L.S.Azhgirey, N.G.Anischenko, V.D.Bartenev, A.Bazhanov, N.A.Blinov, N.S.Borisov, S.B.Borzakov, Yu.T.Borzunov, T.N.Borzunova, E.I.Bunyatova, V.F.Burinov, Yu.P.Bushuev, L.P.Chernenko, E.V.Chernykh, V.F.Chumakov, S.A.Dolgii, A.N.Fedorov, V.V.Fimushkin, M.Finger1, M.Finger,Jr., L.B.Golovanov, D.K.Guriev, A.Janata2, A.D.Kirillov, V.G.Kolomiets, E.V.Komogorov, A.D.Kovalenko, I.G.Konskii, N.I.Kochelev, V.A.Krasnov, E.S.Kuzmin, N.A.Kuzmin, V.P.Ladygin, A.B.Lazarev, A.N.Livanov, P.K.Maniakov, E.A.Matyushevsky, A.A.Morozov, A.B.Neganov, G.P.Nikolaevsky, A.A.Nomofilov, Tz.Panteleev3, Yu.K.Pilipenko, I.L.Pisarev, Yu.A.Plis, R.V.Polyakova, V.Yu.Prytkov, P.A.Rukoyatkin, V.I.Sharov, T.V.Shavrina, S.N.Shilov, R.A.Shindin, Yu.A.Shishov, V.B.Shutov, O.N.Schevelev, M.Slunechka, V.Slunechkova, A.Yu.Starikov, L.N.Strunov, Yu.A.Usov, T.A.Vasiliev, V.I.Volkov, E.I.Vorobiev, I.P.Yudin, I.V.Zaitsev, V.N.Zhmyrov, • Joint Institute for Nuclear Research, Dubna • 1 Charles University, Praha, Czech Republic • 2 Institute for Nuclear Research, Rez, Czech Republic • 3 Institute for Nuclear Research and Nuclear Energy, BAS, Sofia, Bulgaria V.G.Baryshevsky, K.G.Batrakov, T.I.Klimkovich, S.L.Cherkas • RNNP,Belorussian State University, Belorussia A.I.Kovalev, A.N.Prokofiev, V.A.Schedrov, A.A.Zhdanov • Peterburg Institute of Nuclear Physics, Gatchina G.M.Gurevich • Institute for Nuclear Research, RAS, Moscow V.G.Antonenko, Yu.P.Polunin • Russian Scientific Center "Kurchatov Institute", Moscow F.Lehar. A. de Lesquen • DAPNIA, Saclay, France A.A.Belyaev, A.A.Lukhanin • Kharkov Institute of Physics and Technology, Kharkov, Ukraine Delta-Sigma experimentt

  44. Nucleon-Nucleon Formalism Throughout the project and results publications we used the NN formalism and notations for elastic nucleon-nucleon scattering observables from Bystricky J., Lehar F., Winternitz P. J. Phys. (Paris). 1978. v.39. p. 1. Assuming parity conservation, time-reversal invariance, the Pauli principle, and isospin invariance, the nucleon-nucleon scattering matrix can be written in term of only five invariant amplitudes M(k', k) = ½ [(a+b)+(a-b)(σ1,n)(σ2,n)+(c+d)(σ1,m)(σ2,m)+(c-d)(σ1,l)(σ2,l)+e(σ1+σ2,n)],(1) where σ1 and σ2 are the Pauli 2x2 matrices acting on the first and second nucleon wave functions, and k and k' are unit vectors in the direction of the incident and scattered particles, respectively. The invariant amplitudes a, b, c, d and e are complex functions of two variables, e. g., the center of mass (c. m.) energy k and scattering angle θ. In the forward direction at θ=0, total angular momentum conservation implies that e=0 and a-b=c+d. Similarly at 180º one obtains e=0 and a-b=c-d. The center of mass basis vectors are given by l = (k'+k)/(|k'+k|), m = (k'-k)/(|k'-k|),n = (k'xk)/(|k'xk|).(2) Delta-Sigma experimentt

  45. For the pp, nn, and np interactions, the scattering matrix can be written in term of two matrices M0 and M1 having the same form as Eq. (1) M(k',k) = ¼ M0 [1-(τ1, τ2)] + ¼ M1 [3+(τ1, τ2)],(3) where τ1 and τ2 are isosinglet and isotriplet scattering matrices. Ignoring electromagnetic interaction, one can write M(pp→pp) = M(nn→nn) = M1, M(np→np) = M(pn→pn) = ½ (M1+M0),(4) M(np→pn) = M(pn→np) = ½ (M1-M0). This formalism uses a four-subscript notation Xsrbt for experimental quantities. Subscripts s, r, b, and t refer to the polarization components of the scattered, recoil, beam, and target particles, respectively. For any c. m. observable Xpqik, the following expression holds dσ/dΩ Xpqik = ¼ Tr (σ1pσ2q M σ1iσ2k M+), (5) where dσ/dΩ = I0000 = ¼ Tr ( M M+),(6) is the unpolarized differential cross section. Delta-Sigma experimentt

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  49. Neutron Beam Parameters • The beam of free quasi-monochromatic neutrons is obtained by break-up of deuterons at 0º in the Beryllium target BT (20 cm×8×8 cm2). • Neutron beam is formed by a set of collimators C1–C4. • The deuteron beam momentum Pd is known with accuracy of~1 %. • The neutron beam has the momentum Pn = Pd /2 with a gaussian momentum spread of FWHM ~ 5 %. • Intensity of prepared neutron beam at Tn= 2.0 GeVwas ~4∙106 n/cycle. • For theΔσL measurements, the neutron spins are rotated from verticaldirection to the direction of beam momentum by spin rotating magnetSRM. Delta-Sigma experimentt

  50. Experimental set-up for the ΔσL,T(np) measurements. Layout of the detectors for the neutron transmission measurement. C4 − last neutron beam collimator, 25 mm in diameter; M1, M2 − monitor neutron detector modules; PPT − polarized proton target; T1, T2, T3 − neutron transmission detector modules; CH2 − converters; NP − neutron beam profile monitor; A − anticoincidence scintillation counters; S1 − S4 − coincidence scintillation counters; PC − multiwire proportional chambers. Delta-Sigma experimentt

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