Nuclear response in the<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mmultiscripts><mml:mrow><mml:mi mathvariant="normal">Fe</mml:mi></mml:mrow><mml:mprescripts /><mml:mrow /><mml:mrow><mml:mn>54</mml:mn></mml:mrow><mml:mrow /><mml:mrow /></mml:mmultiscripts></mml:mrow></mml:math>(<i>p</i>→,<i>p</i>→’) reaction at 290 MeV

Häusser, O.; Vetterli, M. C.; Fergerson, R. W.; Glashausser, C.; Jeppesen, R. H.; Smith, R. K.; Abegg, R.; Baker, F. T.; Celler, Anna; Helmer, R. L.; Henderson, R.; Hicks, K.; Iqbal, M.J.; Jackson, K. P.; Jones, K. W.; Lisantti, J.; Mildenberger, J.; Miller, C. A.; Sawafta, R.; Yen, S.

doi:10.1103/physrevc.43.230

Cited by 29 publications

(23 citation statements)

References 58 publications

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“…For the (e, e ) data a statistical limit due to the radiative tail in the spectra and difficulties to distinguish M 1 and M 2 form factors for weak transitions dominate the uncertainties. The (p, p ) spectra are background-free up to the neutron threshold and the background due to quasifree scattering is small approaching 2 mb/(sr MeV) [60] at higher excitation energies (cf. Fig.…”

Section: Comparison With the (E E ) Resultsmentioning

confidence: 99%

Search for weakM1transitions inCa48with inelastic proton scattering

Mathy¹,

Birkhan²,

Matsubara³

et al. 2017

Phys. Rev. C

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Background: The quenching of spin-isospin modes in nuclei is an important field of research in nuclear structure. It has an impact on astrophysical reaction rates and on fundamental processes like neutrinoless double-β decay. Gamow-Teller (GT) and spinflip M 1 strengths are quenched. Concerning the latter, the J π = 1 + resonance in the doubly magic nucleus 48 Ca, dominated by a single transition, serves as a reference case.Purpose: The aim of the present work is a search for weak M 1 transitions in 48 Ca with a high-resolution (p, p ) experiment at 295 MeV and forward angles including 0 • and a comparison to results from a similar study using backward-angle electron scattering at low momentum transfers in order to estimate their contribution to the total B(M 1) strength in 48 Ca. Methods: The spin-M 1 cross sections of individual peaks in the spectra are deduced with a multipole decomposition analysis (MDA) and converted to reduced spin-M 1 transition strengths using the unit cross section method. For a comparison with electron scattering results, corresponding reduced B(M 1) transition strengths are extracted following the approach outlined in J. Birkhan et al., Phys. Rev. C 93, 041302(R) (2016). Results: In total, 30 peaks containing a M 1 contribution are found in the excitation energy region 7 − 13 MeV. The resulting B(M 1) strength distribution compares well to the electron scattering results considering different factors limiting the sensitivity in both experiments and the enhanced importance of mechanisms breaking the proportionality of nuclear cross sections and electromagnetic matrix elements for weak transitions as studied here. The total strength of 1.14(7) µ 2 N deduced assuming a non-quenched isoscalar part of the (p, p ) cross sections agrees with the (e, e ) result of 1.21(13) µ 2 N . A binwise analysis above 10 MeV provides an upper limit of 1.51(17) µ 2 N . Conclusions: The present results confirm the previous electron scattering work that weak transitions contribute about 25% to the total B(M 1) strength in 48 Ca and the quenching factors of GT and spin-M 1 strength are then comparable in f p-shell nuclei. Thus, the role of meson-exchange currents (MECs) seems to be negligible in 48 Ca, in contrast to sd-shell nuclei.

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Section: Comparison With the (E E ) Resultsmentioning

confidence: 99%

Search for weakM1transitions inCa48with inelastic proton scattering

Mathy¹,

Birkhan²,

Matsubara³

et al. 2017

Phys. Rev. C

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“…However, differences in S""( FIG. 6. Spectra of relative spin responses presented as in Fig. apparently due mainly to differences on oo (Fig.…”

Section: Systematic Features Of Data Formentioning

confidence: 98%

“…There, the first clear determination of the distribution of spin-dipole strength relative to sum-rule predictions was described and a spin-dipole resonance (SDR) approximately exhausting the sum rule was observed. Similar multipole decompositions for Fe have been performed [6] [5] and Fe [6] assumed that o, may be determined approximately from the appropriately isospin-averaged free NN force (determined from the Love-Franey t matrix [8,9]). The analyses presented here for Ca and Ca are also based on this assumption.…”

Section: Introductionmentioning

confidence: 99%

Spin decomposition of the responses ofCa44andCa
Baker
¹
,
Bimbot
²
,
Fergerson
³

et al. 1991
Phys. Rev. C
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Angular distributions of the double-difFerential cross section d o /dQ dE {o ) and the spin-flip probability S""have been measured for inclusive proton inelastic scattering from Ca at 290 MeV and from 'Ca at 318 MeV. Excitation energies up to about 50 MeV for~Ca and 40 MeV for 'Ca have been investigated over the laboratory angular ranges of 3' to 12' for Ca and 3' to 9 for Ca. Multipole decompositions of angular distributions of both the spin-Rip cross section o. S""and the estimated cross section for AS =0 transitions have been performed. Distributions of strengths were deduced for hL = 1, hS =0 {the giant dipole), AL =2, AS =0 (the giant quadrupole), AL =0, AS = 1 {the magnetic dipole), hL = 1, AS =1 {the spin dipole), and AL =2, ES =1 {the spin quadrupole). The ES =0 summed strengths for Ca are lower than for " Ca and 'Ca. The spin-dipole summed strengths are found to be approximately independent of A. For Ca, essentially all M1 strength observed was in the 10.23 MeV 1+ state; for Ca, M1 strength was observed to be fragmented over a range of 7 to 18 Mev.

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“…Inspection of the structure of T~[ see Eq. (2)] shows that in this case the coincident observables are written in terms of bilinear products of the same A; 's as are the singles observables. The crucial difference between these two sets of equations is the presence of t; (k) in the definition of the coincident observables, replacing the 8, ', for the singles observables.…”

Section: Formalismmentioning

confidence: 99%

“…In the intermediate energy regime (-150 -500 MeV), where the impulse approximation is generally considered a valid reaction model, much of our knowledge as to how the free nucleonnucleon (NN) interaction is modified by the presence of the nuclear medium has been obtained through measurements of (p, p') spin-transfer observables, for transitions to either discrete nuclear states [I] or to the continuum via quasielastic scattering [2].In these types of singles (p, p') measurements, however, no more than eight independent quantities can be measured, assuming angular momentum and parity conservation.…”

Section: Introductionmentioning

confidence: 99%

Simultaneous measurements of (p→, p→′) and (
Wells
¹
,
Wissink
²
,
Bacher
³

et al. 1995
Phys. Rev. C
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We have made simultaneous measurements of singles (p, p') spin-transfer observables and coincident (p, p'y) yields and asymmetries for the 15.11 MeV, 1+, T= 1 state in ' C, at an incident proton bombarding energy of 200 MeV. Data were taken at four proton scattering angles ranging from 0"' = 5. 5' to 16.5'. Both vertical (normal to the reaction plane) and horizontal (in-plane) incident beam polarizations were used, which allowed us to extract 16 different observables for this transition. In particular, using the (p, p y) reaction, we measured the sideways and longitudinal analyzing powers, Dos and DOL, which vanish identically in the (p,p ) reaction. Detailed comparisons of all observables to calculations done in both relativistic and nonrelativistic formalisms are presented. Surprisingly, a relativistic description in which knock-on exchange processes are not explicitly included provides the best overall agreement with the data.PACS number(s): 25.40.Ep, 24.70.+s, 25.90.+k

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Nuclear response in theFe54(p→,p→’) reaction at 290 MeV

Cited by 29 publications

References 58 publications

Search for weakM1transitions inCa48with inelastic proton scattering

Search for weakM1transitions inCa48with inelastic proton scattering

Spin decomposition of the responses ofCa44andCa
Baker
¹
,
Bimbot
²
,
Fergerson
³

et al. 1991
Phys. Rev. C
Self Cite
14
0
0
0
View full text Add to dashboard Cite

Simultaneous measurements of (p→, p→′) and (
Wells
¹
,
Wissink
²
,
Bacher
³

et al. 1995
Phys. Rev. C
Self Cite

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Nuclear response in theFe54(p→,p→’) reaction at 290 MeV

Cited by 29 publications

References 58 publications

Search for weakM1transitions inCa48with inelastic proton scattering

Search for weakM1transitions inCa48with inelastic proton scattering

Spin decomposition of the responses ofCa44andCaBaker1, Bimbot2, Fergerson3 et al. 1991Phys. Rev. CSelf Cite14000View full textAdd to dashboardCite

Simultaneous measurements of (p→, p→′) and (Wells1, Wissink2, Bacher3 et al. 1995Phys. Rev. CSelf Cite

Contact Info

Product

Resources

About

Spin decomposition of the responses ofCa44andCa
Baker
¹
,
Bimbot
²
,
Fergerson
³

et al. 1991
Phys. Rev. C
Self Cite
14
0
0
0
View full text Add to dashboard Cite

Simultaneous measurements of (p→, p→′) and (
Wells
¹
,
Wissink
²
,
Bacher
³

et al. 1995
Phys. Rev. C
Self Cite