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A further comment on the itep neutrino mass experiments
Volume 159B, number 4,5,6
A FURTHER COMMENT
PHYSICS LETTERS
26 September 1985
ON THE ITEP NEUTRINO MASS EXPERIMENTS
K a r l Erik B E R G K V I S T Research Institute of Physics, S- 104 05 Stockholm, Sweden
Received 2 May 1985
It is argued that as a result of only partial allowance for shake-up effects in the conversion line used to define the instrumental response function, the ITEP-84 (Leipzig) claim of evidence of finite neutrino mass should be expected to involve an overestimate by some (1400 -+ 400)(eV) 2 in the stated value M2 = (1215 -+ 130)(eV) 2, making the claim of finite mass untenable.
In a recent paper [1] in this journal we have questioned the claim o f evidence o f finite neutrino mass as issued by the ITEP group in the proceedings from the Brighton HEP conference - ITEP-83 [2]. Shortly after the submission o f our paper [1], a further claim of evidence o f finite neutrino mass from the same group became available in the proceedings from the Leipzig HEP conference - ITEP-84 [3]. In this brief note we apply our type of analysis o f ref. [1] to the new ITEP claim [3]. Again the conclusion seems anavoidable that the claim of evidence of finite mass remains unsupported b y the material so far released. In ITEP-84 [3] an allowance for shake-up effects in the reference conversion line is made when inferring the particle optical response function. The allowance made implies a reduction by about 100 (eV) 2 in the reference line MSES (truncated mean square energy spread as defined in ref. [1]), as can be deduced from figs. 2 and 3 in ref. [3]. This reduction should be compared with the (800 + 200) (eV) 2 allotted to shake-up effects in our investigation [1]. Since the basic assumption for establishing the shake-up correction in ITEP-83 does not seem too compelling * 1, our own , t A shake-up process results from the difference in the initial and final state atomic hamiltonian caused by the vacancy of the ejected conversion electron. From this basic point, the central assumption in the ITEP-84 shake-up correction that the shake-up spectrum is independent of in which shell the vacancy is produced - seems to need further qualification. -
408
more direct determination o f the effect should - until, o f course, actually shown to be wrong (cf. ref. [1 ]) be given priority. Hence some ( 8 0 0 - 1 0 0 -+ 200 = 700 -+ 200) (eV) 2 should be expected to be unaccounted for in the ITEP-84 shake-up correction o f the response function. This, according to ref. [ 1], will tend the inferred value o f M 2 coming out roughly some (1400 + 400) (eV) 2 too large, cancelling the finite mass suggestionM 2 = (1215 + 130) (eV) 2 o f ITEP-84 [3]. As to the earlier work ITEP-83 [2], subject to our analysis in ref. [111 it is a striking circumstance that ITEP-84 [3] is contradictory to ITEP-83 [2] when it comes to statements as to the response function actually involved in the analysis in ITEP-83. The contradiction concerns a key issue in ref. [2] and can obviously not be genuinely settled by an external viewer ,2. I f the response function used in ITEP-83 [2] is as originally stated, the result of our analysis in ref. [1 ] o f ITEP-83 of course still applies to this work. The implications of ITEP-83 [2] and ITEP-84 [3] are then compatible, both investigations actually furnishing no indication of finite neutrino mass once the appropriate shake-up MSES in the response function is taken into account. *~ The basic response function as originally (and plainly) stated in ref. [2] is the 'Matural" response function, to be expected to lead to a correct inference of My2. No statement is given in ref. [2] that any other meaning is intended to apply to the fitted value of My2.
Volume 159B, number 4,5,6
PHYSICS LETTERS
If, on the other hand, the response function assumed in the analysis of ITEP-83 [2] data is as now told in ITEP-84 [3], then the implications of ITEP-83 and ITEP-84 actually seem to be incompatible, possibly indicating a so far unrecognized lack of uniqueness in the ITEP fitting procedure. According to ref. [3], the basic response function involved in ITEP-83 data fitting is a symmetrized distribution, obtained by mirroring the high-energy slope of the reference line on a vertical through the line peak, after first having corrected for a 14.7 eV lorentzian. Although there is, a priori, no reason why such a choice o f basic response function should lead to a correct value o f M 2 ,2, from our analysis in ref. [1] it can be deduced, that when the MSES of the actually recorded and exhibited reference line in ref. [2] (with the lorentzian unfolded) is properly corrected for shake-up effects, we do indeed get an MSES value close to that of the symmetrized line now [3] said to have been assumed in the analysis of ITEP-83. The fitting of data in ITEP-83 should hence be expected to furnish the correct value o f M 2. The value stated in ref. [2] isM 2 --~ 1100 (eV) 2 (M = 33 eV). This result is hard to reconcile with the corrected figure M 2 ~ 0, obtained above for the more extensive data of ITEP-84 [3]. We emphasize that our analysis - here and in ref. [1] - of the ITEP data fitting in terms of the MSES of the constituent distributions in the overall response function does not pretend to be more than a crude tool for estimating quantitatively how an inferred value o f M 2 should be expected to vary when changing the MSES of one of the constituent distributions. A simple check on one aspect o f the method was given in a footnote in ref. [1]. As a further illustration, let us use the MSES cast analysis to work out how the inferred value o f M 2 in ITEP-84 [3] should be expected to change when going from the valine final state spectrum to the bare nucleus single-level spectrum in the data analysis. The valine final state spectrum assumed in ITEP-84 is as calculated by Kaplan et al. [4]. Evaluating the MSES of the histogram given for valine in this work we obtain about 360 (eV) 2. This means [1] that we should expect M 2 to come out some 700 (eV) 2 larger in the valine case than in the bare-nucleus case. Going to table 2 in ITEP-84 [3] we find that the inferred value o f M 2 does indeed change from (190 -+ 80) (eV) 2 to the (1215 + 130) (eV) 2, in fair agreement with the anticipated change *a
26 September 1985
Changing the atomic final state spectrum MSES by a certain amount should be roughly equivalent to changing the basic response function MSES by the same amount, as far as the resulting value o f M 2 is concerned. The quoted example therefore strongly indicates that our MSES patterned analysis does indeed possess the necessary degree of accuracy for our points to be made. In summary, until further arguments are advanced, no consistent indication of a finite neutrino mass seems presently possible to ascribe to the data of ITEP.83 and ITEP-84.
Appendix. For the sake of completeness we provide here the derivation of the MSES additivity property referred to in ref. [ 1]. We assume a recording device, having at the energy setting E ' the response R(E-E') to electrons of energy E, and consider the recording of a conversion line having an intrinsic energy distribution L(E1- E) around the central energy value E = E 1. For the functionsR and L we assume (cf. ref. [1]): fR(E-E')
d e ' = 1,
f R(E-E')E' de' =E,
(1, 2)
fL(E1-E)dE=l,
fL(E1-ElEdE=E1,
(3,4t
For the recorded line profile
D(E') = f L ( e l - e ) R ( e - e ' )
D(E') we have
de
(5)
The center of gravity value E ' = e b for the distribution D is
= r e ' de'
-- fL(F
f L(E1-E)R(E-E') de
-e)dE fR(e-e')e' de'
= fL(e~-E)EdE = E l ,
(6)
where we have used (2) and (4). For the MSES of D we hence have
,a For our particular discussion to apply, we must assume that the valine final state spectrum used in ITEP-84 is strictly as defined by the histogram in ref. [4]. The histogram concerned accounts for 87% of the total transition intensity. 409
Volume 159B, number 4,5,6 (MSES)D =
PHYSICS LETTERS
ment actually diverges - this is one o f the reasons for patterning the analysis in ref. [ 1] in terms of truncated distributions.
f D(E')(F, '- E1)2 dE'
= ffL(E1-E)R(E-E')(E'-E1)
2 dEdE'
R eferen ce$
= fL(E 1 - E) de f R ( E - E')(E'-E1) 2 d E ' =
fL(el-e)de fg(e-E')
X [ ( E - g ' ) + (E 1 - g ) ] 2 d E ' = (MSES)R + (MSES)L,
(7)
where we have used (3), (1) and (2). F o r eq. (7) to be significant, the second moments o f R and L must exist. I f L is assumed to be strictly lorentzian, its second too.
410
26 September 1985
[1] K.E. Bergkvist, Phys. Lett. 154B (1985) 224. [2] S. Boris et al., Proc. Intern. Europhysies Conf. on High energy physics (Brighton, UK, 1983) (Rutherford and Appleton Laboratory, Chilton, UK) p. 386. [3] S. Boris et al., Proe. 22nd Intern. Conf. on High energy physics (leipzig, DDR, 1984) Vol. 1, eds. A. Meyer and E. Wieezorek (lnstitut fiir Hochenergiephysik, 1615 Zeuthen, GDR) p. 259. [4] J. Kaplan, V. Smutnui and G. Smelov, Dokl. Akad. Nauk SSSR 279 (1984) 1110.
A FURTHER COMMENT
PHYSICS LETTERS
26 September 1985
ON THE ITEP NEUTRINO MASS EXPERIMENTS
K a r l Erik B E R G K V I S T Research Institute of Physics, S- 104 05 Stockholm, Sweden
Received 2 May 1985
It is argued that as a result of only partial allowance for shake-up effects in the conversion line used to define the instrumental response function, the ITEP-84 (Leipzig) claim of evidence of finite neutrino mass should be expected to involve an overestimate by some (1400 -+ 400)(eV) 2 in the stated value M2 = (1215 -+ 130)(eV) 2, making the claim of finite mass untenable.
In a recent paper [1] in this journal we have questioned the claim o f evidence o f finite neutrino mass as issued by the ITEP group in the proceedings from the Brighton HEP conference - ITEP-83 [2]. Shortly after the submission o f our paper [1], a further claim of evidence o f finite neutrino mass from the same group became available in the proceedings from the Leipzig HEP conference - ITEP-84 [3]. In this brief note we apply our type of analysis o f ref. [1] to the new ITEP claim [3]. Again the conclusion seems anavoidable that the claim of evidence of finite mass remains unsupported b y the material so far released. In ITEP-84 [3] an allowance for shake-up effects in the reference conversion line is made when inferring the particle optical response function. The allowance made implies a reduction by about 100 (eV) 2 in the reference line MSES (truncated mean square energy spread as defined in ref. [1]), as can be deduced from figs. 2 and 3 in ref. [3]. This reduction should be compared with the (800 + 200) (eV) 2 allotted to shake-up effects in our investigation [1]. Since the basic assumption for establishing the shake-up correction in ITEP-83 does not seem too compelling * 1, our own , t A shake-up process results from the difference in the initial and final state atomic hamiltonian caused by the vacancy of the ejected conversion electron. From this basic point, the central assumption in the ITEP-84 shake-up correction that the shake-up spectrum is independent of in which shell the vacancy is produced - seems to need further qualification. -
408
more direct determination o f the effect should - until, o f course, actually shown to be wrong (cf. ref. [1 ]) be given priority. Hence some ( 8 0 0 - 1 0 0 -+ 200 = 700 -+ 200) (eV) 2 should be expected to be unaccounted for in the ITEP-84 shake-up correction o f the response function. This, according to ref. [ 1], will tend the inferred value o f M 2 coming out roughly some (1400 + 400) (eV) 2 too large, cancelling the finite mass suggestionM 2 = (1215 + 130) (eV) 2 o f ITEP-84 [3]. As to the earlier work ITEP-83 [2], subject to our analysis in ref. [111 it is a striking circumstance that ITEP-84 [3] is contradictory to ITEP-83 [2] when it comes to statements as to the response function actually involved in the analysis in ITEP-83. The contradiction concerns a key issue in ref. [2] and can obviously not be genuinely settled by an external viewer ,2. I f the response function used in ITEP-83 [2] is as originally stated, the result of our analysis in ref. [1 ] o f ITEP-83 of course still applies to this work. The implications of ITEP-83 [2] and ITEP-84 [3] are then compatible, both investigations actually furnishing no indication of finite neutrino mass once the appropriate shake-up MSES in the response function is taken into account. *~ The basic response function as originally (and plainly) stated in ref. [2] is the 'Matural" response function, to be expected to lead to a correct inference of My2. No statement is given in ref. [2] that any other meaning is intended to apply to the fitted value of My2.
Volume 159B, number 4,5,6
PHYSICS LETTERS
If, on the other hand, the response function assumed in the analysis of ITEP-83 [2] data is as now told in ITEP-84 [3], then the implications of ITEP-83 and ITEP-84 actually seem to be incompatible, possibly indicating a so far unrecognized lack of uniqueness in the ITEP fitting procedure. According to ref. [3], the basic response function involved in ITEP-83 data fitting is a symmetrized distribution, obtained by mirroring the high-energy slope of the reference line on a vertical through the line peak, after first having corrected for a 14.7 eV lorentzian. Although there is, a priori, no reason why such a choice o f basic response function should lead to a correct value o f M 2 ,2, from our analysis in ref. [1] it can be deduced, that when the MSES of the actually recorded and exhibited reference line in ref. [2] (with the lorentzian unfolded) is properly corrected for shake-up effects, we do indeed get an MSES value close to that of the symmetrized line now [3] said to have been assumed in the analysis of ITEP-83. The fitting of data in ITEP-83 should hence be expected to furnish the correct value o f M 2. The value stated in ref. [2] isM 2 --~ 1100 (eV) 2 (M = 33 eV). This result is hard to reconcile with the corrected figure M 2 ~ 0, obtained above for the more extensive data of ITEP-84 [3]. We emphasize that our analysis - here and in ref. [1] - of the ITEP data fitting in terms of the MSES of the constituent distributions in the overall response function does not pretend to be more than a crude tool for estimating quantitatively how an inferred value o f M 2 should be expected to vary when changing the MSES of one of the constituent distributions. A simple check on one aspect o f the method was given in a footnote in ref. [1]. As a further illustration, let us use the MSES cast analysis to work out how the inferred value o f M 2 in ITEP-84 [3] should be expected to change when going from the valine final state spectrum to the bare nucleus single-level spectrum in the data analysis. The valine final state spectrum assumed in ITEP-84 is as calculated by Kaplan et al. [4]. Evaluating the MSES of the histogram given for valine in this work we obtain about 360 (eV) 2. This means [1] that we should expect M 2 to come out some 700 (eV) 2 larger in the valine case than in the bare-nucleus case. Going to table 2 in ITEP-84 [3] we find that the inferred value o f M 2 does indeed change from (190 -+ 80) (eV) 2 to the (1215 + 130) (eV) 2, in fair agreement with the anticipated change *a
26 September 1985
Changing the atomic final state spectrum MSES by a certain amount should be roughly equivalent to changing the basic response function MSES by the same amount, as far as the resulting value o f M 2 is concerned. The quoted example therefore strongly indicates that our MSES patterned analysis does indeed possess the necessary degree of accuracy for our points to be made. In summary, until further arguments are advanced, no consistent indication of a finite neutrino mass seems presently possible to ascribe to the data of ITEP.83 and ITEP-84.
Appendix. For the sake of completeness we provide here the derivation of the MSES additivity property referred to in ref. [ 1]. We assume a recording device, having at the energy setting E ' the response R(E-E') to electrons of energy E, and consider the recording of a conversion line having an intrinsic energy distribution L(E1- E) around the central energy value E = E 1. For the functionsR and L we assume (cf. ref. [1]): fR(E-E')
d e ' = 1,
f R(E-E')E' de' =E,
(1, 2)
fL(E1-E)dE=l,
fL(E1-ElEdE=E1,
(3,4t
For the recorded line profile
D(E') = f L ( e l - e ) R ( e - e ' )
D(E') we have
de
(5)
The center of gravity value E ' = e b for the distribution D is
= r e ' de'
-- fL(F
f L(E1-E)R(E-E') de
-e)dE fR(e-e')e' de'
= fL(e~-E)EdE = E l ,
(6)
where we have used (2) and (4). For the MSES of D we hence have
,a For our particular discussion to apply, we must assume that the valine final state spectrum used in ITEP-84 is strictly as defined by the histogram in ref. [4]. The histogram concerned accounts for 87% of the total transition intensity. 409
Volume 159B, number 4,5,6 (MSES)D =
PHYSICS LETTERS
ment actually diverges - this is one o f the reasons for patterning the analysis in ref. [ 1] in terms of truncated distributions.
f D(E')(F, '- E1)2 dE'
= ffL(E1-E)R(E-E')(E'-E1)
2 dEdE'
R eferen ce$
= fL(E 1 - E) de f R ( E - E')(E'-E1) 2 d E ' =
fL(el-e)de fg(e-E')
X [ ( E - g ' ) + (E 1 - g ) ] 2 d E ' = (MSES)R + (MSES)L,
(7)
where we have used (3), (1) and (2). F o r eq. (7) to be significant, the second moments o f R and L must exist. I f L is assumed to be strictly lorentzian, its second too.
410
26 September 1985
[1] K.E. Bergkvist, Phys. Lett. 154B (1985) 224. [2] S. Boris et al., Proc. Intern. Europhysies Conf. on High energy physics (Brighton, UK, 1983) (Rutherford and Appleton Laboratory, Chilton, UK) p. 386. [3] S. Boris et al., Proe. 22nd Intern. Conf. on High energy physics (leipzig, DDR, 1984) Vol. 1, eds. A. Meyer and E. Wieezorek (lnstitut fiir Hochenergiephysik, 1615 Zeuthen, GDR) p. 259. [4] J. Kaplan, V. Smutnui and G. Smelov, Dokl. Akad. Nauk SSSR 279 (1984) 1110.