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Jason and the Golden Fleece

LNS. Determining NME by Heavy-Ion Double Charge Exchange Clementina Agodi - Laboratori Nazionali del Sud – INFN - Italy. Jason and the Golden Fleece. Clementina Agodi, Neutrino Oscillation Workshop Conca Specchiulla (Otranto) -September 7-14, 2014. LNS. Introduction.

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Jason and the Golden Fleece

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  1. LNS Determining NME by Heavy-Ion Double Charge Exchange Clementina Agodi - Laboratori Nazionali del Sud – INFN - Italy Jason and the Golden Fleece Clementina Agodi, Neutrino Oscillation Workshop Conca Specchiulla (Otranto) -September 7-14, 2014

  2. LNS Introduction Neutrinoless double beta decayispotentially the best resource to probe the Majorana or Dirac nature of neutrino and to extractitseffective mass. 2ββ-decay predicted by the Standard Model 0ββ-decay forbidden by the Standard Model Process mediated by the weak interaction occurring in even-even nuclei where the single -decay is energetically forbidden The knowledge of the nuclearmatrixelements for the neutrinoless double beta decayisfundamental for neutrino physics. Clementina Agodi, Neutrino Oscillation Workshop Conca Specchiulla (Otranto) -September 7-14, 2014

  3. LNS The role of nuclear physics In the 0νββ double beta decay the decay rate can be expressed as a product of independent factors, that also depends on a function containing physics beyond the Standard Model throught the masses and the mixing coefficients of the neutrinos species : A lot of new physics inside ! Thus, if the M0νββ nuclear matrix elements were known with sufficient precision, the neutrino mass could be established from 0νββ decay rate measurements. Clementina Agodi, Neutrino Oscillation Workshop Conca Specchiulla (Otranto) -September 7-14, 2014

  4. LNS The state of the art New physics for the nextdecades! The evaluation of NME: • Calculations (still sizeable uncertainties): QRPA, Large scale shell model, IBM ….. • Giuliani and A. Poves, Adv. in High Energy Phys., 857016 (2012) • Measurements(still not conclusive for 0): • (+, -) • single charge exchange (3He,t) • electron capture • transfer reactions … E. Caurier, et al., PRL 100 (2008) 052503 N. L. Vaquero, et al., PRL 111 (2013) 142501 J. Barea, PRC 87 (2013) 014315 T. R. Rodriguez, PLB 719 (2013) 174 F.Simkovic, PRC 77 (2008) 045503. F.Iachello et al. NPB 237-238 (2013) 21 - 23 N. Auerbach, Ann. Of Phys. 192 (1989) 77 S.J. Freeman and J.P. Schiffer JPG 39 (2012) 124004 D.Frekers, Prog. Part. Nucl. Phys. 64 (2010) 281 J.P. Schiffer, et al., PRL 100 (2008) 112501 D.Frekers et al. NPA 916 (2013)219 - 240 Clementina Agodi, Neutrino Oscillation Workshop Conca Specchiulla (Otranto) -September 7-14, 2014

  5. LNS A new esperimental tool: DCE Clementina Agodi, Neutrino Oscillation Workshop Conca Specchiulla (Otranto) -September 7-14, 2014

  6. LNS HI Double Charge Exchange HI Double charge exchange reactions are characterized by the transfer of two units of the isospin (ΔTz= ± 2) leaving the mass number unchanged Direct mechanism: isospin-flipprocesses 2 n 18Ne+11Li 20Ne+18Li E-x = -10.8 MeV 2 p E-x = -10.6 MeV 2 p HeavyIon DCE direct E-x = -10.8 MeV 16O+13B 18O+11B 2 n Sequential mechanism: two-proton plus two-neutron transfer or vice-versa 11B(18O,18Ne)11Li E-x = -18 MeV D.R.Bes, O. Dragun, E.E. Maqueda, Nucl. Phys. A 405 (1983) 313. Clementina Agodi, Neutrino Oscillation Workshop Conca Specchiulla (Otranto) -September 7-14, 2014

  7. LNS Heavy-ion DCE • Sequential nucleon transfer mechanism 4th order: • Brink’s Kinematical matching conditions 1 D.M.Brink, et al., Phys. Lett. B 40 (1972) 37 • Meson exchange mechanism 2nd order: • Momentum transfer correction of the GT unit cross- section 2 T.N.Taddeucci, et al, Nucl. Phys. A 469 (1987) 125 Direct DCE cross-sectionas the product of the twocharge-exchangeones Clementina Agodi, Neutrino Oscillation Workshop Conca Specchiulla (Otranto) -September 7-14, 2014

  8. LNS 0 vs DCE • Initial and final states: Parent/daughter states of the 0ββare the same as those of the target/residual nuclei in the DCE; • Spin-Isospin mathematical structure of the transition operator: Fermi, Gamow-Teller and rank-2 tensor together with higher L components are present in both cases; • Large momentum transfer: A linear momentum transfer as high as 100 MeV/c or so is characteristic of both processes; • Non-locality: both processes are characterized by two vertices localized in two valence nucleons. In the ground to ground state transitions in particular a pair of protons/neutrons is converted in a pair of neutrons/protons so the non-locality is affected by basic pairing correlation length; • In-medium processes: both processes happen in the same nuclear medium, thus quenching phenomena are expected to be similar; • Relevantoff-shell propagation in the intermediate channel: both processes proceed via the same intermediate nuclei off-energy-shell even up to 100 MeV. Clementina Agodi, Neutrino Oscillation Workshop Conca Specchiulla (Otranto) -September 7-14, 2014

  9. LNS Factorization of the charge exchange cross-section for single CEX: -decay transition strengths (reduced matrix elements) α= Fermi (F) or Gamow Teller (GT) Mj(α)2= B(α) C.J Guess,et al, PRC 83 064318 (2011) The factor F(q,) describes the shape of the cross-section distribution as a function of the linear momentum transfer and the excitation energy. unit cross-section T.N.Taddeucci, et al, Nucl. Phys. A 469 (1987) 125 In the hypothesis of a surface localized process (for direct quasi elastic processes): generalization to DCE: In analogy to the single charge-exchange, the dependence of the cross-section from q is represented by a Bessel function. unit cross-section Clementina Agodi, Neutrino Oscillation Workshop Conca Specchiulla (Otranto) -September 7-14, 2014

  10. LNS Single charge-exchange The unit cross section JST Volume integral of the VST potential Double charge-exchange In the σ(Ep,A) the specificity of the single or double charge exchange is express through the volume integrals of the potentials: the other factors are general features of the scattering. Ifknownitwouldallow to determine the NME from DCE cross sectionmeasurement, whateveris the strenghtfragmentation Thisiswhathappens in single chargeexchange : B(GT;CEX)/B(GT;-decay)  1 within a few % especially for the strongesttransitions In a simplemodelone can assume that the DCE processis just a secondorderchargeexchange, whereprojectile and target exchangetwoincorrelatedisovectorvirtualmesons. Clementina Agodi, Neutrino Oscillation Workshop Conca Specchiulla (Otranto) -September 7-14, 2014

  11. LNS Pastexperimentalattempts 40Ca(14C,14O)40Ar @ 51 MeV 10° < θlab< 30° Q = -4.8 MeV • Few experimental attempts: • not conclusive because of the very poor yields in the measured energy spectra and the lack of angular distributions, due to the very low cross-sections involved. • not easy to measure, in the same experimental conditions, the different competitive reaction channels (limit due to the prohibitive small cross-sections). D.M.Drake, et al., Phys. Rev. Lett. 45 (1980) 1765 C.H.Dasso, et al., Phys. Rev. C 34 (1986) 743 C. Agodi Roma - CSN3 31- Marzo 2014

  12. LNS DCE at LNS Clementina Agodi, Neutrino Oscillation Workshop Conca Specchiulla (Otranto) -September 7-14, 2014

  13. LNS The experiment: 40Ca(18O,18Ne)40Ar@LNS • 18O7+beam from LNS Cyclotron at 270 MeV (10 pnA) • 40Casolid target of 300 μg/cm2 • Ejectiles detected by the MAGNEX spectrometer • Angular setting 16O + 42Ca 18F + 40K 18Ne + 40Ar 18O + 40Ca 20Ne + 38Ar Measured Not measured Clementina Agodi, Neutrino Oscillation Workshop Conca Specchiulla (Otranto) -September 7-14, 2014

  14. LNS Measured Resolution: Energy E/E  1/1000 Angle Δθ  0.3° Mass Δm/m  1/160 The experimental SET-UP@ LNS:MAGNEX F. Cappuzzello et al., MAGNEX: an innovative large acceptance spectrometer for nuclear reaction studies, in Magnets: Types, Uses and Safety (Nova Publisher Inc., NY, 2011) pp. 1–63.

  15. LNS Preliminary results Measured energy spectrum of 40Ar at very forward angles with an energy resolution of FWHM ~ 0.5 MeV . Differential cross-section of the transition 0Cag.s.(18O,18Ne)40Arg.s. @ 270 Mev FWHM ~ 0.5 MeV ! preliminary The 40Ar 0+ ground state is well separated from both the first excited state 40Ar 2+ at 1.46 MeV and the 18Ne excited state at 1.887 MeV The position of the minima iswelldescribed by a Besselfunction : such an oscillation pattern isnotexpectd in complexmultistep transfer reactions. dσDCE /dΩ=11μb/sr at θcm=00 Clementina Agodi, Neutrino Oscillation Workshop Conca Specchiulla (Otranto) -September 7-14, 2014

  16. LNS The NUMEN Project C. Agodi, F. Cappuzzello, M. Bondì, L. Calabretta, D. Carbone, M. Cavallaro, M. Colonna, A. Cunsolo, G. Cuttone, A. Foti, P. Finocchiaro, V. Greco, L. Pandola, D. Rifuggiato, S. Tudisco INFN - Laboratori Nazionali del Sud, Catania, Italy; INFN - Sezione di Catania, Catania, Italy; Dipartimento di Fisica e Astronomia, Università di Catania, Catania, Italy; Clementina Agodi, Neutrino Oscillation Workshop Conca Specchiulla (Otranto) -September 7-14, 2014

  17. LNS Few “hot” cases To optimize the experimental conditions to open a new and challenging research field, we propose an experimental campaign using, as probe, few targets of interest as candidate nuclei for the 0νββ decay such as 76Se, 76Ge, 116Cd, 130Te : Clementina Agodi, Neutrino Oscillation Workshop Conca Specchiulla (Otranto) -September 7-14, 2014

  18. LNS The experimental campaign To perform the experimental campaign that we propose it is necessary a Facility Upgrade • CS upgrade to give high beam intensity • a new focal plane detector, suitable to resist to high rates 3. a modular gamma detector system for coincidences measurements Experimental campaign A series of experimental campaigns at high beam intensities and long experimental runs in order to reach in each experiment integrated charge of hundreds of mC up to C, for the experiments in coincidences, spanning all the variety of 0νββ decay candidate isotopes, like: 48Ca,82Se,96Zr,100Mo,110Pd,124Sn,128Te,130Te,136Xe,148Nd,150Nd,154Sm,160Gd,198Pt Clementina Agodi, Neutrino Oscillation Workshop Conca Specchiulla (Otranto) -September 7-14, 2014

  19. LNS The Holy Graal:the unit cross section Studying if the σDCE is a smooth function of Ep and A is the most ambitious goal of our project This requires that a systematic set of appropriate data is built, facing the relative experimental challanges connected with the low cross sections and resolution requests Goal N.1 for NUMEN A new generation of DCE constrained 0 NME theoretical calculations can emerge The measured DCE cross sections provide a powerful tool for theory in order to give very stringent onstraints in the NME estimation The DCE processes can be artificially generated in the lab! (Few labs. as the LNS) Goal N.2 for NUMEN Providing relative NME information on hot cases of 0 is strongly required by the community in order to compare the sensitivity of different half-life experiments This could impact in future development of the field. Goal N.3 for NUMEN Clementina Agodi, Neutrino Oscillation Workshop Conca Specchiulla (Otranto) -September 7-14, 2014

  20. LNS Summary • An innovative technique to access the nuclear matrix elements entering in the expression of the life time of the 0νββdecay by relevant cross sections ofdouble charge exchange reactions is proposed. • The basic point is the coincidence of the initial and final state wave-functions in the two classes of processes and the similarity of the transition operators. • First pioneering experimental results obtained at the INFN-LNS with MAGNEX for the 40Ca(18O,18Ne)40Ar reaction at 270 MeV, give encouraging indication on the capability of the proposed technique to access relevant quantitative information. • A main limitation on the beam current delivered by the accelerator and the maximum rate accepted by the MAGNEX focal plane detector must be sensibly overcome with the upgrade of the LNS facilities. rigorous determination of the absolute cross sections values for all the system of interest, to the challenging determination of the 0νββdecay nuclear matrix elements An amazing time for new and challenging nuclear research field in the era of the physics beyond the Standard Model! Neutrino Oscillation Workshop - Conca Specchiulla (Otranto, Lecce, Italy) -September 7-14, 2014

  21. LNS …experimental limits Determination of nuclear matrix elements seems to be at our reach… BUT : • About one order of magnitude more yield would have been necessary for the reaction studied, especially at backward angles in order to extract more quantitative information on the background generated by competing multi-nucleon transfer reactions; • In some cases gas target will be necessary, e.g. 136Xe or 130Xe, which are normally much thinner than solid state ones, with a consequent reduction of the collected yield; • In some cases the energy resolution we can provide (about half MeV) is not enough to separate the ground state form the excited states in the final nucleus. In these cases the coincident detection of -rays from the de-excitation of the populated states is necessary, but at the price of the collected yield. An upgraded set-up, able to work with two orders of magnitude more current than the present, is thus necessary! This goal can be achieved by a substantial change in the technologies used in the beam extraction and in the detection of the ejectiles Clementina Agodi, Neutrino Oscillation Workshop Conca Specchiulla (Otranto) -September 7-14, 2014

  22. LNS Check the validity of the factorization We deduce the unit cross section for the DCE processassuming a double GT Transition. Takinginto account single chargeexchange data: 40Ca response to chargeexchange BGT=0.069(6) About half of the total GT strenght goes to the 2.73 MeV state of 40K Courtesy of Prof. Y. Fujita Clementina Agodi, Neutrino Oscillation Workshop Conca Specchiulla (Otranto) -September 7-14, 2014

  23. Assuming incoherent sum of F + GT The 40Ca(18O,18Ne)40Ar case: 13 μb/sr 7 μb/sr Here we estimated the uncertainty by checking the sensitivity of the results to the used parameters and found that it is is about a factor 2. To be compared to: Despite the approximations used and the simplified scheme considered these results indicate that the DCE unit cross section is at our reach, in analogy to the single charge exchange! Clementina Agodi, Neutrino Oscillation Workshop Conca Specchiulla (Otranto) -September 7-14, 2014

  24. Double chargeexchangereactions atRCNP (Japan) 12C(18O,18Ne)12Be @ 80 AMeV • GrandRaidenspectrometer • Beamenergy 80AMev • Beamintensity 25 pnA Limitation: Energy resolution 1.2 MeV Interest for 48Ca (CANDLES) T. Uesaka et al., Prog. of Theor. Phys. 196 (2012) 150 H.Matsubara et al. Few Body Syst. 2013 DOI 10.1007/s00601-012-0586-9

  25. LNS A fundamental property Residual interaction Optical potential The complicated many-body heavy-ion scattering problem is largely simplified for direct quasi-elastic reactions V (r ,) = U (r) + W(r ,) For charge exchange reactions the W(r ,) is ‘small’ and can be treated perturbatively In addition the reactions are strongly localized at the surface of the colliding systems and consequently large overlap of nuclear densities are avoided Accurate description in fully quantum approach, eg. Distorted Wave techniques Microscopic derived double folding potentials are good choices for U (r) Microscopic form factors work for charge exchange reactions Neutrino Oscillation Workshop - Conca Specchiulla (Otranto, Lecce, Italy) -September 7-14, 2014

  26. The image at the focus is meaningful if it can give us information about the object in its position! To see means to reconstruct The reconstruction problem Inversion of the transport matrix The optical aberrations make this reconstruction difficult F. Cappuzzello, et al., NIM A 638, (2011) 74 PhysicalParameters at the target GeometricalParametersmeasuredat the FPD

  27. MAGNEX: a ray-reconstruction spectrometer • Possible definition: spectrometer reconstructing a net image by an optically aberrated one Practically One needs • High order inversion algorithms (10th order for MAGNEX) • Specialized Focal Plane Detectors (FPD) to measure positions and angles at the focus • Detailed knowledge of the magnetic field maps inversion Long learning step

  28. 20Ne 21Ne 22Ne LNS 19Ne 18Ne ECPcorr (Ch) Na Xfoc (m) Ne F Eresid (Ch) Eresid (Ch) The experimental feasibility PILOT experiment 40Ca(18O,18Ne)40Ar @ 270 MeV with the competing processes: 40Ca(18O,18F)40K single charge exchange 40Ca(18O,20Ne)40Ar two-proton transfer 40Ca(18O,16O)42Ca two-neutron transfer. C. Agodi Roma - CSN3 31- Marzo 2014

  29. LNS Moving towards hot-cases • The (18O,18Ne) reaction is particularly advantageous, but it is of β+β+ kind; • None of the reactions of β-β- kind looks like as favourable as the (18O,18Ne). (18Ne,18O) requires a radioactive beam (20Ne,20O) or (12C,12Be) have smaller B(GT) • In some cases gas target will be necessary, e.g. 136Xe or 130Xe • In some cases the energy resolution is not enough to separate the g.s. from the excited states in the final nucleus  Coincident detection of -rays • A strong fragmentation of the double GT strength is known in the nuclei of interest compared to the 40Ca. Neutrino Oscillation Workshop - Conca Specchiulla (Otranto, Lecce, Italy) -September 7-14, 2014

  30. LNS Assuming pure GT In the 40Ca(18O,18Ne)40 case 0.15  0.07 To be compared to: B2[GT;18Ogs(0+)18Fgs(1+)] * B2[GT;40Cags(0+)40K0-6MeV(1+)] = 0.0075 = 3.56 Y. Fujita private communication 0.098 D.J.Mercer et al. Phys. Rev. C 49 (1994) 3104 corresponding to the product of the known B(GT) values for the transitions in the projectile and target Neutrino Oscillation Workshop - Conca Specchiulla (Otranto, Lecce, Italy) -September 7-14, 2014

  31. LNS Measured energy spectrum Measured energy spectrum of 40Ar at very forward angles. FWHM ~ 0.5 MeV ! The 40Ar 0+ ground state iswellseparated from both the first excited state 40Ar 2+at 1.46 MeV and the 18Ne excited state at 1.887 MeV C. Agodi Roma - CSN3 31- Marzo 2014

  32. LNS Preliminary results Differential cross-section of the transition 0Cag.s.(18O,18Ne)40Arg.s. @ 270 Mev preliminary The position of the minima iswelldescribed by a Besselfunction : such an oscillation pattern isnotexpectd in complexmultistep transfer reactions. dσDCE /dΩ=11μb/sr at θcm=00 Clementina Agodi, Neutrino Oscillation Workshop Conca Specchiulla (Otranto) -September 7-14, 2014

  33. LNS Assuming pure F The 40Ca(18O,18Ne)40Ar case: 32 μb/sr 0.77 0.44  0.2 To be compared to: B2[F;18Ogs(0+)18Fgs(1+)] * B2[F;40Cags(0+)40K0-6MeV(1+)] = 0.138 = 4.00 0.55 Y. Fujita private communication D.J.Mercer et al. Phys. Rev. C 49 (1994) 3104 Neutrino Oscillation Workshop - Conca Specchiulla (Otranto, Lecce, Italy) -September 7-14, 2014

  34. LNS 40Ca(18O,18Ne)40Ar @ 270 MeV Projectile 18O 18Ne Super-allowed transition GT strength not fragmented 2.73 1+ 18F B(GT) = 1.09 B(GT) = 3.27 g.s. 4- 40K B(GT)total < 0.15 B(GT)=0.023 B(GT)=0.069(6) Target GT strength not much fragmented g.s. 0+ 40Ca g.s. 0+ 40Ar Neutrino Oscillation Workshop - Conca Specchiulla (Otranto, Lecce, Italy) -September 7-14, 2014

  35. Double Charge Exchange on 40Ca ground state 1f5/2 1f5/2 1f7/2 1f7/2 1d3/2 1d3/2 2s1/2 2s1/2 1d5/2 1d5/2 1p1/2 1p1/2 1p3/2 1p3/2 1s1/2 1s1/2 p p n n p n 40Cag.s. 40Arg.s. 40Kg.s.

  36. Major upgrade of LNS facilities • The CS accelerator current upgrade (from 100 W to 5-10 kW); • The MAGNEX focal plane detector will be upgraded from 1 khz to 100 khz • The MAGNEX maximum magnetic rigidity will be increased • An array of detectors for -rays measurement in coincidence with MAGNEX will be built • The beam transport line transmission efficiency will be upgraded from about 70% to nearly 100% • The target technology for intense heavy-ion beams will be developed

  37. LNS The Phases of NUMEN project • Phase1: The experimental feasibility • Phase2: “hot” cases optimizing the experimental conditions and getting first results • Phase3: The facility Upgrade (Cyclotron, MAGNEX, beam line, …..): • Phase4 : The systematic experimental campaign Preliminary time table

  38. LNS Preliminary spectrum of 38Ar 0°< θlab<10° 40Ca(18O,20Ne)38Ar @ 270 MeV 16O(18O,20Ne)14C Preliminary 12C(18O,20Ne)10Be counts l = 8 l = 6 g.s.* + 2.167 l = 2 l = 4 Suppression of l = 0 in the transfer g.s. l = 0 E* (MeV) C. Agodi Roma - CSN3 31- Marzo 2014

  39. Pastexperimentalattempts 24Mg(18O,18Ne)24Ne at 1.37GeV J.Blomgren, et al., Phys. Lett. B 362 (1995) 34

  40. LNS Few experimental attempts 40Ca(14C,14O)40Ar @ 51 MeV 10° < θlab< 30° Q = -4.8 MeV • Few experimental attempts: • not conclusive because of the very poor yields in the measured energy spectra and the lack of angular distributions, due to the very low cross-sections involved. • not easy to measure, in the same experimental conditions, the different competitive reaction channels (limit due to the prohibitive small cross-sections). D.M.Drake, et al., Phys. Rev. Lett. 45 (1980) 1765 C.H.Dasso, et al., Phys. Rev. C 34 (1986) 743 Neutrino Oscillation Workshop - Conca Specchiulla (Otranto, Lecce, Italy) -September 7-14, 2014

  41. Beyond the standard model LNS Seesaw mechanism Dirac mass will be the same order as the others. (0.1~10 GeV) Right handed Majorana mass will be at GUT scale 1015 GeV C. Agodi Roma - CSN3 31- Marzo 2014

  42. LNS The role of the involved nuclei • The nucleon transfer reaction cross sections can be deduced from simple dynamic considerations, according to semi-classical arguments, when the incident energy is above the Coulomb barrier. • Assuming a mechanism where a cluster is transferred: the cross section tends to maximize within a Q-window, which depends on the reaction Qgg, on the target, on the projectile radii and on the incident energy. • Brink’s matching conditions • D.M. Brink, Phys. Lett. B 40 (1972) 37-40 • The survival of a preformed pair in a transfer process is favoured when the initial and final orbitals are the same

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