for useful discussions and assistance. We also thank R. Siemssen and F. Iachello for the hospital... more for useful discussions and assistance. We also thank R. Siemssen and F. Iachello for the hospitality provided to us at the Kernfysisch Versneller Instituut, Groningen, where part of this work was carried out. This work was funded in part by the National Science Foundation Grant No. PHY-79-02654-A01 and by Stichtung voor Fundamenteel Onderzoek der Materie (FOM). 'A. Arima and F. Iachello, Ann.
The one-photon | xutri /b m/|=2 nuclear magnetic resonance in /sup 12/B (/b I/=1) was investigate... more The one-photon | xutri /b m/|=2 nuclear magnetic resonance in /sup 12/B (/b I/=1) was investigated. It is found that this resonance is quasi-allowed near low-field level crossings. Some of its applications are considered.Anglai
The helicity, /b h//sup -/, of mu /sup -/ in pi -decay has been determined as positive (/b h//sup... more The helicity, /b h//sup -/, of mu /sup -/ in pi -decay has been determined as positive (/b h//sup -/>or=+0.90) from the average polarization, /b P/ /sub av/ equiv , of /sup 12/B produced in the mu /sup -/+/sup 12 /C rarr nu /sub mu /+/sup 12/B reaction. Dynamical information is also on mu -capture: (i) the weak magnetism form factor, mu =4.5+/-1.1, and (ii) the sum of the induced pseudoscalar (/b g //sub P/) and the 2nd class induced tensor (/b g//sub T/) couplings versus /b g//sub A/, (/b g/ /sub P/+/b g//sub Gamma /)//b g//sub A /=7.1+/-2.7. The latter result, adopting the `canonical' value of /b g//sub P///b g//sub A/, leads to /b g//sub T ///b g//sub A/=+1+/-2/7 which is compatible with zero and in strong contradiction with the value sime -6 recently advocated by Kubodera, Delorme and Rho (see Phys. Rev. Lett., vol.38, p.312, (1977)).Anglai
The heliclty, h-, of ~- m n-decay has been determined aspoSltlve (h->/+0.90) from the average ... more The heliclty, h-, of ~- m n-decay has been determined aspoSltlve (h->/+0.90) from the average polarlzatmn, Pay- = <JB "su>, of 12B produced m the ~- + 12C ~ v ~ + 12B reactmn We obtain also dynamical reformation on u-capture 0) the weak magnetism form factor, t ~ = 4.5 +- 1 1, and (n) the sum of the reduced pseudoscalar (gp) and the 2nd class induced tensor (gT) couphngs versusg A, (gp +gr)/gA = 7 1-+ 2 7 The latter esult, adopting the "canonical " value ofgp/gA, leads to gT/gA = +1-+ 2.7 which is compatible with zero and m strong contradiction wlth the value ~-6 recently advocated by Kubodera, Delorme and Rho We present here a measurement of the average polarization, Pav-- ( JB "$g), of 12B in the allowed (0 + ~ 1 +) reaction/1- + 12C ~ v u + 12B(g.s.). The result can be exploited in two ways, VlZ. (a) to deter-mine the hehcity of the / J- from rr-decay, following an old suggestion of Jackson et al. [1]. (This is analo-gous to the ve-helicity experiment...
Charge distributions of phosphorus ions in carbon foils up to 200 ,gcm-2 have been measured betwe... more Charge distributions of phosphorus ions in carbon foils up to 200 ,gcm-2 have been measured between 72 and 123 MeV. The parameters of the semi-empirical formulae are discussed.
The average polarization of /sup 12/B produced by the capture of polarized muons in /sup 12/C has... more The average polarization of /sup 12/B produced by the capture of polarized muons in /sup 12/C has been measured using recoil implantation techniques. From the result the average polarization of the /sup 12/B ground state /sup 12/B(0) corresponding to the /sup 12/C rarr /sup 12/B(0) Gamow Teller reaction is deduced: /b J//sub mu /(0)=0.43+/-0.10. The sizeable deviation of this polarization from the value of 2/3, characteristic of a `bare' 0 /sup +/ rarr 1/sup +/ process, is a fair evidence for induced axial-vector interaction(s) in muon capture. The ratio of the induced pseudoscalar and the axial-vector coupling constants is deduced to be: /b g//sub P//sup mu ///b g//sub A//sup mu /=12+/-5.
The results of a new measurement of the 2S ~-2P3~, splitting S' in the muonic ion (P-4He)+ are pr... more The results of a new measurement of the 2S ~-2P3~, splitting S' in the muonic ion (P-4He)+ are presented. We found SâP = 1527.5 f 0.3 meV. Using the new, recently determined, value of the rms charge radius for 4He we obtain for the difference D, between S,'~and the corresponding theoretical prediction, the value D = 0.2 f 4.2 meV : this value directly eonfums, assuming p-e universality, the QED vacuum polarization prediction to 0.25~. ATOMIC PHYSICS Muonic`He ; measured fine structure ; deduced QED vacuum polarization .
With a Variable Energy Positron beam annihilation energy spectra are measured in eight different ... more With a Variable Energy Positron beam annihilation energy spectra are measured in eight different porous anodic layers on aluminium. Analysing the Doppler broadening of the annihilation line information can be achieved concerning layer characteristics like thickness. The presence of orthopositronium in the poses can be determined by comparing the peak to Compton ratios of the inner aluminium substrate and the porous layers.
The heliclty, h-, of ~-m n-decay has been determined as poSltlve (h->/+0.90) from the average pol... more The heliclty, h-, of ~-m n-decay has been determined as poSltlve (h->/+0.90) from the average polarlzatmn, Pay-= <JB "su>, of 12B produced m the ~-+ 12C ~ v~ + 12B reactmn We obtain also dynamical reformation on u-capture 0) the weak magnetism form factor, t~ = 4.5 +-1 1, and (n) the sum of the reduced pseudoscalar (gp) and the 2nd class induced tensor (gT) couphngs versusg A, (gp +gr)/gA = 7 1-+ 2 7 The latter result, adopting the "canonical" value ofgp/gA, leads to gT/gA = +1-+ 2.7 which is compatible with zero and m strong contradiction wlth the value ~-6 recently advocated by Kubodera, Delorme and Rho
Using the experimental data on the capture rate and the recoil polarization in the reaction p-+ I... more Using the experimental data on the capture rate and the recoil polarization in the reaction p-+ I 2 C-+ l 2~ + v p the weak-magnetism form factor is deduced independently of a specific value of the pseudoscalar form factor g p (q 2). It is found to be in good agreement with the conserved-vector-current hypothesis. Then we look at the range of compatibility of the induced form factors for the given experimental data.
Journal of Radioanalytical and Nuclear Chemistry Articles, 1996
Porous anodic layers were grown on aluminium alloys under different anodizing conditions, Positro... more Porous anodic layers were grown on aluminium alloys under different anodizing conditions, Positron annihilation energy spectra were measured as a function of the positron energy, O~ho-positronium formation in the porous layer was detected. The positron characteristics could be con-elated to known parameters of the layers. This demonstrates that the positron annihilation method is a particularly useful technique to eharacterise the anodic layers.
2 x 10/sup -4/ per disintergration was found for any l competing with its superallowed BETA decay... more 2 x 10/sup -4/ per disintergration was found for any l competing with its superallowed BETA decay. (auth)
We describe a simple experiment for measuring the helicity of the muonic neutrino, hνμ, directly.... more We describe a simple experiment for measuring the helicity of the muonic neutrino, hνμ, directly. This experiment is the muonic analog of the celebrated Brookhaven experiment for the electron neutrino. Both are based on measuring the longitudinal polarization PL of the recoils in a 0→1 lepton capture; here we exploit 12C(μ−, νμ)12B(g.s.), determining the polarization of 12B through its β‐decay asymmetry. Recoils going into a specific hemisphere are chosen by the trick of ’’selective implantation.’’ The paper includes an elementary derivation of the requisite theoretical expressions. We find hνμ = −1.06(11), i.e., −1.0 with considerable accuracy.
Nuclear Instruments and Methods in Physics Research
A new fast gas-filled multiwire counter of high efficiency has been developed for experiments bas... more A new fast gas-filled multiwire counter of high efficiency has been developed for experiments based on the observation of low energy X-rays. A time resolution down to 30 ns (fwhm) has been achieved at 2.3 keV. Detector and electronic designs are detailed.
crystal occurs. Figure 3(b) can of course also describe two successive spontaneous scatterings; t... more crystal occurs. Figure 3(b) can of course also describe two successive spontaneous scatterings; the observed intensity at &"0+~sF is about i0' too large for such an explariation.
for useful discussions and assistance. We also thank R. Siemssen and F. Iachello for the hospital... more for useful discussions and assistance. We also thank R. Siemssen and F. Iachello for the hospitality provided to us at the Kernfysisch Versneller Instituut, Groningen, where part of this work was carried out. This work was funded in part by the National Science Foundation Grant No. PHY-79-02654-A01 and by Stichtung voor Fundamenteel Onderzoek der Materie (FOM). 'A. Arima and F. Iachello, Ann.
The one-photon | xutri /b m/|=2 nuclear magnetic resonance in /sup 12/B (/b I/=1) was investigate... more The one-photon | xutri /b m/|=2 nuclear magnetic resonance in /sup 12/B (/b I/=1) was investigated. It is found that this resonance is quasi-allowed near low-field level crossings. Some of its applications are considered.Anglai
The helicity, /b h//sup -/, of mu /sup -/ in pi -decay has been determined as positive (/b h//sup... more The helicity, /b h//sup -/, of mu /sup -/ in pi -decay has been determined as positive (/b h//sup -/>or=+0.90) from the average polarization, /b P/ /sub av/ equiv , of /sup 12/B produced in the mu /sup -/+/sup 12 /C rarr nu /sub mu /+/sup 12/B reaction. Dynamical information is also on mu -capture: (i) the weak magnetism form factor, mu =4.5+/-1.1, and (ii) the sum of the induced pseudoscalar (/b g //sub P/) and the 2nd class induced tensor (/b g//sub T/) couplings versus /b g//sub A/, (/b g/ /sub P/+/b g//sub Gamma /)//b g//sub A /=7.1+/-2.7. The latter result, adopting the `canonical' value of /b g//sub P///b g//sub A/, leads to /b g//sub T ///b g//sub A/=+1+/-2/7 which is compatible with zero and in strong contradiction with the value sime -6 recently advocated by Kubodera, Delorme and Rho (see Phys. Rev. Lett., vol.38, p.312, (1977)).Anglai
The heliclty, h-, of ~- m n-decay has been determined aspoSltlve (h->/+0.90) from the average ... more The heliclty, h-, of ~- m n-decay has been determined aspoSltlve (h->/+0.90) from the average polarlzatmn, Pay- = <JB "su>, of 12B produced m the ~- + 12C ~ v ~ + 12B reactmn We obtain also dynamical reformation on u-capture 0) the weak magnetism form factor, t ~ = 4.5 +- 1 1, and (n) the sum of the reduced pseudoscalar (gp) and the 2nd class induced tensor (gT) couphngs versusg A, (gp +gr)/gA = 7 1-+ 2 7 The latter esult, adopting the "canonical " value ofgp/gA, leads to gT/gA = +1-+ 2.7 which is compatible with zero and m strong contradiction wlth the value ~-6 recently advocated by Kubodera, Delorme and Rho We present here a measurement of the average polarization, Pav-- ( JB "$g), of 12B in the allowed (0 + ~ 1 +) reaction/1- + 12C ~ v u + 12B(g.s.). The result can be exploited in two ways, VlZ. (a) to deter-mine the hehcity of the / J- from rr-decay, following an old suggestion of Jackson et al. [1]. (This is analo-gous to the ve-helicity experiment...
Charge distributions of phosphorus ions in carbon foils up to 200 ,gcm-2 have been measured betwe... more Charge distributions of phosphorus ions in carbon foils up to 200 ,gcm-2 have been measured between 72 and 123 MeV. The parameters of the semi-empirical formulae are discussed.
The average polarization of /sup 12/B produced by the capture of polarized muons in /sup 12/C has... more The average polarization of /sup 12/B produced by the capture of polarized muons in /sup 12/C has been measured using recoil implantation techniques. From the result the average polarization of the /sup 12/B ground state /sup 12/B(0) corresponding to the /sup 12/C rarr /sup 12/B(0) Gamow Teller reaction is deduced: /b J//sub mu /(0)=0.43+/-0.10. The sizeable deviation of this polarization from the value of 2/3, characteristic of a `bare' 0 /sup +/ rarr 1/sup +/ process, is a fair evidence for induced axial-vector interaction(s) in muon capture. The ratio of the induced pseudoscalar and the axial-vector coupling constants is deduced to be: /b g//sub P//sup mu ///b g//sub A//sup mu /=12+/-5.
The results of a new measurement of the 2S ~-2P3~, splitting S' in the muonic ion (P-4He)+ are pr... more The results of a new measurement of the 2S ~-2P3~, splitting S' in the muonic ion (P-4He)+ are presented. We found SâP = 1527.5 f 0.3 meV. Using the new, recently determined, value of the rms charge radius for 4He we obtain for the difference D, between S,'~and the corresponding theoretical prediction, the value D = 0.2 f 4.2 meV : this value directly eonfums, assuming p-e universality, the QED vacuum polarization prediction to 0.25~. ATOMIC PHYSICS Muonic`He ; measured fine structure ; deduced QED vacuum polarization .
With a Variable Energy Positron beam annihilation energy spectra are measured in eight different ... more With a Variable Energy Positron beam annihilation energy spectra are measured in eight different porous anodic layers on aluminium. Analysing the Doppler broadening of the annihilation line information can be achieved concerning layer characteristics like thickness. The presence of orthopositronium in the poses can be determined by comparing the peak to Compton ratios of the inner aluminium substrate and the porous layers.
The heliclty, h-, of ~-m n-decay has been determined as poSltlve (h->/+0.90) from the average pol... more The heliclty, h-, of ~-m n-decay has been determined as poSltlve (h->/+0.90) from the average polarlzatmn, Pay-= <JB "su>, of 12B produced m the ~-+ 12C ~ v~ + 12B reactmn We obtain also dynamical reformation on u-capture 0) the weak magnetism form factor, t~ = 4.5 +-1 1, and (n) the sum of the reduced pseudoscalar (gp) and the 2nd class induced tensor (gT) couphngs versusg A, (gp +gr)/gA = 7 1-+ 2 7 The latter result, adopting the "canonical" value ofgp/gA, leads to gT/gA = +1-+ 2.7 which is compatible with zero and m strong contradiction wlth the value ~-6 recently advocated by Kubodera, Delorme and Rho
Using the experimental data on the capture rate and the recoil polarization in the reaction p-+ I... more Using the experimental data on the capture rate and the recoil polarization in the reaction p-+ I 2 C-+ l 2~ + v p the weak-magnetism form factor is deduced independently of a specific value of the pseudoscalar form factor g p (q 2). It is found to be in good agreement with the conserved-vector-current hypothesis. Then we look at the range of compatibility of the induced form factors for the given experimental data.
Journal of Radioanalytical and Nuclear Chemistry Articles, 1996
Porous anodic layers were grown on aluminium alloys under different anodizing conditions, Positro... more Porous anodic layers were grown on aluminium alloys under different anodizing conditions, Positron annihilation energy spectra were measured as a function of the positron energy, O~ho-positronium formation in the porous layer was detected. The positron characteristics could be con-elated to known parameters of the layers. This demonstrates that the positron annihilation method is a particularly useful technique to eharacterise the anodic layers.
2 x 10/sup -4/ per disintergration was found for any l competing with its superallowed BETA decay... more 2 x 10/sup -4/ per disintergration was found for any l competing with its superallowed BETA decay. (auth)
We describe a simple experiment for measuring the helicity of the muonic neutrino, hνμ, directly.... more We describe a simple experiment for measuring the helicity of the muonic neutrino, hνμ, directly. This experiment is the muonic analog of the celebrated Brookhaven experiment for the electron neutrino. Both are based on measuring the longitudinal polarization PL of the recoils in a 0→1 lepton capture; here we exploit 12C(μ−, νμ)12B(g.s.), determining the polarization of 12B through its β‐decay asymmetry. Recoils going into a specific hemisphere are chosen by the trick of ’’selective implantation.’’ The paper includes an elementary derivation of the requisite theoretical expressions. We find hνμ = −1.06(11), i.e., −1.0 with considerable accuracy.
Nuclear Instruments and Methods in Physics Research
A new fast gas-filled multiwire counter of high efficiency has been developed for experiments bas... more A new fast gas-filled multiwire counter of high efficiency has been developed for experiments based on the observation of low energy X-rays. A time resolution down to 30 ns (fwhm) has been achieved at 2.3 keV. Detector and electronic designs are detailed.
crystal occurs. Figure 3(b) can of course also describe two successive spontaneous scatterings; t... more crystal occurs. Figure 3(b) can of course also describe two successive spontaneous scatterings; the observed intensity at &"0+~sF is about i0' too large for such an explariation.
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Papers by L. Palffy