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14/29/20151 Symposium on Astro-Particle and Nuclear Physics In Honour of 70th Birthday of Prof. Q.N. Usmani 4/29/2015.

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Presentation on theme: "14/29/20151 Symposium on Astro-Particle and Nuclear Physics In Honour of 70th Birthday of Prof. Q.N. Usmani 4/29/2015."— Presentation transcript:

1 14/29/20151 Symposium on Astro-Particle and Nuclear Physics In Honour of 70th Birthday of Prof. Q.N. Usmani 4/29/2015

2 2

3 Professor M. Z. Rahman Khan 4/29/20153

4 4 4 Energies of multi-strange α-cluster hypernuclei using variational Monte Carlo Method MOHAMMAD SHOEB Department of Physics, Aligarh Muslim University, Aligarh , India 4/29/2015

5 5 5 Outline 1.Introduction 2. Hamiltonian in α-cluster model 3. Potential models 4.Variational wavefunctions 5. Results and discussion 6. Summary 4/29/2015

6 Introduction: Aim of nuclear physics Complete knowledge of the interaction among octet of baryons in a unified way 4/29/2015

7 7 Motivation of studying Strange and multi- strange hypernuclei to extract interaction between hyperon-N and hyperon-hyperon  Existence of hypernuclei  represent a new state of matter  may exhibit new symmetries, selection rules, etc. 4/29/2015

8 8  Presence of hyperon(s) may modify the properties of the core  moment inertia of deformed nucleus  rotational and vibrational states structure of nucleus  Hypernucleus provides us a opportunity to investigate properties of hyperon(s) in nuclear medium  Hyperon(s) inside nuclei may be used as probe to study the nuclear structure 4/29/2015

9 9 9 It is believed that hyperons matter forming the inner core of neutron stars would have significant effect on their properties. Schaffner-Bielich [NP 804(2008)309 and ref. their in ] has discussed that hypernuclear potential depths, two-body hyperon- nucleon and hyperon three-body forces as well as hyperon-hyperon interaction would 4/29/2015

10 10 Therefore, determination of hyperon- nucleon and hyperon-hyperon interaction becomes very important for investigating the properties of neutron stars. have a impact on the maximum mass, mass- radius relation, and cooling properties of neutron stars. 4/29/2015

11 11 Hypernuclear physics is likely to play key role in the study:  Properties of neutron stars  Equation state of nuclear matter Figure in the next slide shows interdisciplinary nature of hypernuclei linking particle, nuclear, many-body, astrophysics etc. [ref. Erni et al arXiv: hep-ex/ ] 4/29/2015

12 124/29/2015

13 134/29/ Segr table 4/29/2015

14 14 Extension of the nuclear chart in a new dimension, strangeness S 4/29/2015

15 15 -Hypernuclear events, ( ground and excited states), or (Hida event ) and 4/29/2015

16 16 Hypernuclear experiments planned or operative at various (nine) laboratories all over the World 4/29/2015

17 17 Experimental facilities for hypernuclear physics program List of a few leading laboratories where Hypernuclear physics program to produce and identify hypernuclei with strangeness S= -1 to -3 is being pursued TJNAF(Thomas Jefferson National Accelerator Facility) at Newport news in USA Electro-production FINUDA(FIsica NUclearea DA NE): A special accelerator, DA NE (Double Annular ring For Nice Experiment), designed at INFN (Instituto Nazionale di Fisica Nucleare) 4/29/2015

18 184/29/ MeV ( M=1020 MeV, 20s) Head on collision decaysCopious production A beam of of extremely high intensity and precise low energy is expected to insert “strangeness” inside nucleus to produce hypernuclei. 4/29/2015

19 19 J-PARC(Japan Proton Accelerator Research Complex) at KEK: Already a rich data related to both the spectroscopy and decay of hypernuclei at KEK have been measured. Program for production and unambiguous identification of  hypernuclei and excited states using reaction ( )  Excited states of double-Λ hypernuclei 4/29/ /29/2015

20 20 ANDA ( ANnihilation at DArmstadt ): A beam hits primary target to produce ; Stopping and absorption of in the secondary target produce hypernucei. Program to produce S= -3, -hypernucle i 4/29/ /29/2015

21 21 In primary target In secondary target, e.g. Li, Be, B, Schematic picture describing production of double Λ hypernuclei at PANDA 4/29/2015

22 22 Multi-strange hypernuclei Schaffner et al [Ann. Phys.(NY)235(1994) 35 ] observed that a would become particle stable against the strong decay if a sufficient number of bound ’s Pauli blocked this decay mode. Thus is the lightest system suggested to study. At present production of multi- strange hypernuclei seems to be impossible. 4/29/ /29/2015

23 23 However, it will interesting to theoretically study the stability of multi-strange systems. Such a study is likely to have implication on future experimental efforts in producing, identifying and measuring the properties of multi-strange hypernuclei. Therefore, we have included in our study multi-strange hypernuclei apart from strange ones. 4/29/2015

24 244/29/ Hamiltonian in α-cluster model Hypernuclei studied in the α-cluster model using VMC s-shell: p-shell: Systems within rectangular boxes are the ones whose stability predictions are to be made. 4/29/2015

25 25 Hamiltonian for the five-body system in  Ξαα model with α treated as rigid : 4 5 α α Ξ Λ Λ 4/29/2015

26 264/29/ …..(1) K. E. operator,potential energy for the phenomenological dispersive three-body potential with Yukawa form factors. the particle pair 4/29/2015

27 274/29/ Hamiltonian forin ΛΛααα model ….(2) α α α Λ Λ phenomenological repulsive three-body potential with Gaussian form factors 4/29/2015

28 284/29/ Potential Models 3.1 Two-body potentials Three-range Gaussian BB(=ΛΛ,  Ξ) potentials in spin state (=s,t) ….(3) (7.26 MeV) 4/29/2015

29 294/29/ Potentials For = 4/29/2015

30 304/29/ Potentials 4/29/2015

31 314/29/ …(4) (4) 4/29/2015

32 324/29/ potentials for l th partial waves that fit scattering phase shifts. potential of Chien and Brown has been used for only as the energy is not very sensitive to the choice of the potential. Ali-Bodmer potentials 4/29/2015

33 334/29/ Two-range Gaussian potentials Isle fits of and its weak decay modes MSA is obtained from Brueckner-Hartee-Fock Theory and slightly modified to fit of [Euro. Phys. J. 16(2003)21] 4/29/2015

34 344/29/ …..(5) 4/29/2015

35 354/29/ (4). In the previous slide its graph is shown by black color line. WS24 with = 24.0, as suggested by Dover and Gal [Ann.Phys. 146 (1983 )309], has been obtained from a analysis of old and ambiguous data energy = MeV for WS24 and Isle potential = MeV for WS14 4/29/2015

36 364/29/ Phenomenological Three-body potential among and clusters Microscopic calculations of Bodmer and Usmani for shows that contribution of dispersive three-body NN force for the triad where one nucleon from each is participating 4/29/2015

37 374/29/ is quite significant, neglecting it among cluster overbinds and. In cluster model calculation we [Pramana68 (2007)943] have proposed to simulate phenomenologically the dispersive energy in the triad through a simple form (6) 4/29/2015

38 384/29/ and. Phenomenological three-body potential gives good fit to the binding energy and rms radius of in the cluster model for AB [ NP 83(1966)66 & phys Lett B 389(1996)631] potential. ( 7) 4/29/2015

39 394/29/ Variational wavefunctions Construction of good trial wavefunction Physics necessary to describe the ground and excited state Reasonably efficient to compute Wavefunctions are product of two-body correlation functions and the appropriate spin functions 4.1 Wavefunctions (i) and model g.s., degenerate doublet and,. Replacing by gives w.f. for. 4/29/2015

40 404/29/ (ii) and : model g.s., excited state, ( iii) and : model g.s., degenerate doublet, 4/29/2015

41 414/29/ Replacing by gives w.f. of. (iv) Wavefunctions for, and (a) wavefunction for in model: = 4/29/2015

42 424/29/ (b) Wavefunction for : suppress a and a indices in the wavefunction of in (a) above (c) Wavefunction for : suppress a index in the wavefunction of in (a) above (d) Similarly wavefunction for can be obtained. 4/29/2015

43 434/29/ Calculation of correlation function A procedure developed by Urbana group. Solution of the following Schroedinger type equation etc. pair. Potential between particles. 4/29/2015

44 444/29/ /29/2015

45 454/29/ /29/2015

46 464/29/ Procedure for energy calculation ( 8 ) For local operator H the energy can be written in a form suitable for Monte Carlo calculation. Defining local energy 4/29/2015

47 474/29/ and a multivariate probability distribution ( 9) The variational energy is written as (10 ) 4/29/2015

48 484/29/ (11) General procedure for calculation of energy in VMC method: (12) 4/29/2015

49 494/29/ /29/2015

50 504/29/ The energy is evaluated using (i) model of : and (ii) model of : and (iii) model of : and (iv) model of : and Similarly for other hypernuclei 4/29/2015

51 514/29/ To explore the structure of and The quadrupole moment ( ) in the cluster model is calculated using where runs over coordinate of two s, treated as point particles and distances are being measured from the cm of two alphas. 4/29/2015

52 524/29/ Result and Discussion VMC energy: s-Shell Hypernuclei and NSC97e, :ESC00, ND, NSC97b 4/29/2015

53 534/29/ : Isle and WS = 2.09 MeV, =3.45 (Isle) and 3.36 (WS) fm ( ) fm for WS24 Isle WS (12.6, 2.93) (4.8, 2.2) potentials 4/29/2015

54 544/29/ Filikhin et al Faddeev Faddeev-Yakubovsky predicted for  unbound for Isle soft replusive potential  bound for WS24 potential Prediction: binding energy capable of discriminating between radial shape of central potentials, very unlikely, as this violates shape independence of low energy data 4/29/2015

55 554/29/ potential dependent configuration for  stronger potential a configuration speculated i.e. screened by.  configuration for weaker potential Detailed VMC calculation :ESC00, ND, NAGSIM, NSC97e, NSC97b :NSC97e : Isle, WS24, WS14 4/29/2015

56 564/29/ F and FY [Filikhin et al JPG35(2008)] bold face within round bracket 4/29/2015

57 574/29/ Our VMC calculation demonstrates and have negative energies and is bound for WS24 and Isle potential ( while is unbound for Isle potential in F-Y method). Gross property such as energy, not good discriminator of the shapes of the two-body potential. is unbound for WS14 potential. Due to strong conversion process,we will comment on stability of in the last. 4/29/2015

58 584/29/ /29/2015

59 594/29/ Pyramid on triangular isosceles base Isosceles plane Two planes ESC00, NAGSIM, NSC97b and Arms in general increase with decrease in strength of potential but no change in the configuration 4/29/2015

60 604/29/ being screened by two lambdas our calculation support not as opposed to speculation of Filikhin et al configuration whether interaction is weak or strong.[JPG36(2009)045104] 4/29/2015

61 614/29/ p-Shell hypernuclei: (i),,, and Experimental =6.71 MeV = MeV ( MeV assuming, a ray of about 3.0 MeV must have escaped the identification of decay product from the emulsion ). Excited states: = 3.66 MeV Demchi-Yanagi event = MeV 4/29/2015

62 62 Revised = MeV =11.69 MeV 4/29/2015

63 634/29/ and of three-body potential are adjusted to fit ground state energy Ali-Bodmer [Chien-Brown]potential 4/29/2015

64 644/29/ No free potential parameters 4/29/2015

65 654/29/ No free potential parameters Isle+AB MSA+AB 4/29/2015

66 664/29/ No free potential parameters Demchi-Yanagi event B =12.33 MeV 4/29/2015

67 674/29/ Ve quadrupole moment for : Oblate shape : Experimental Q =5.3 N replaced by Prolate Oblate Not much difference between the calculated energy using AB and CB alpha-alpha, Isle and MSA lambad-alpha interactions. Therefore, we consider only AB alpha-alpha and Isle lambda-alpha interactions. 4/29/2015

68 684/29/ = MeV First we analysed sub system Ground state energy = MeV Excited state energy = MeV Energies of ( and ) calculated variationally in cluster model. i) interaction(AB) very repulsive, gives energy -0.7 MeV. ii) + parameters and adjusted to fit the ground state. sitting at the vertices of equilateral triangle. Experimental 4.17 fm 2.4fm c.m. 4/29/2015

69 694/29/ Filikhin et al JPG35 (2008) FY calculation with out 4/29/2015

70 704/29/ and in < for (Shrinkage of core ) > in, wanders at the periphery of core 4/29/2015

71 714/29/ Variational e nergy VMC energy (present work) = MeV in alpha cluster model using Jacobian-coordinate MeV Gaussian-basis function method ( Hiyama et al [Prog.Theo.Phys.97(1997)881] ) Exp MeV Exp MeV 4/29/2015

72 724/29/ Ground and degenerate doublet Interaction (AB)+ (Isle) + + (no free parameter) Exp (-11.69) MeV Prediction 4/29/2015

73 734/29/ : VMC prediction for G.S. energy in model fits energy(-7.26 MeV) + Isle + (AB) VMC Energy = MeV; Predicted binding of = (-31.29)= 24.12MeV 4/29/2015

74 744/29/ in model :VMC Prediction (Isle & WS) + + Filikhin et al JPG35(2008) 4/29/2015

75 754/29/ (ii) Prediction for the energies of and Calculated energy of the above systems in and models using combinations of (Isle, WS24, Ws14), (NSC97e) and (NSC97( b,e), NAGSIM) potentials along with dispersive three-body force. 4/29/2015

76 764/29/ /29/2015

77 774/29/ /29/2015

78 784/29/ VMC energy for < Faddeev method Due to interplay between Calculation limited to s-wave two-body correlations, contribution from partial waves higher than s-wave is simulated. energy for Isle and WS24 differ by 3% for twice of Separation energy in nearly independent of strength. 4/29/2015

79 79 Do the negative energies of and implies stabilty ? No Due to strong conversion depending on the depth of WS potential, these systems can decay as: ; 4/29/2015

80 804/29/ Calculated level scheme for two depths of potential. It seems very unlikely that will ever observed in future experi- mental effort. 4/29/2015

81 81 Note: All the calculations where appears were performed for hyperon. To obtain binding of hypernucleus a coulomb correction 1.5 to 2.0 MeV per alpha particle is to be added to the binding of hypernucleus containing. 4/29/ /29/2015

82 82 6.Summary VMC for binding energy of three-, four-, and five-body alpha cluster s- and p-shell hypernuclei First cluster model VMC calculation for predicting the energy of multistrange hypernuclei VMC energy for is insensitive to the shape of potential as opposed to Faddeev- Yakubovsky method 4/29/ /29/2015

83 83 is unbound and stability depends on potential depth Predicted the energies for and for ground state, and are predicted to be stable for WS14 Demachi-Yanagi event is interpretted as excited and exited state energy of degenerate doublet of explained. 4/29/2015

84 84 Thank you 4/29/2015


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