P.O. Box 500, Batavia, Illinois 60510. D.M. Lazarus and G.C. Smith. Brookhauen National Laboratory. Upton, New York 11973. R. Cameron, A.C. Melissinos,.
Fermi National Accelerator
Laboratory
J?EFfMEAI%Pub92/156
A Search for Solar Axions
F.A.
Nezrick
Fermi National Accelerator Laboratory P.O. Box 500, Batavia, Illinois 60510 D.M.
Lazarus
and G.C. Smith
Brookhauen National Laboratory Upton, New York 11973 R. Cameron,
A.C. Melissinos, University
G. Ruoso,
and Y.K.
Semertzidis
of Rochester
Rochester, New York 14627
June 1992
Submitted
$
to Physical Review Letters
Operated by Universities Research Association Inc. under ContractNo. DE-AC02-76CH03WO tih the United states Depaltment of Energy
Disclaimer
This report was prepared as on account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof nor any of their employees, makes any warranty, erpress or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents thot its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise, does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof
A SEARCH
FOR SOLAR
D.M. Lazarus Brookhaven
R. Cameron,(“)
National
Dept. University
and G.C. Smith
Laboratory,
A.C. MeIissinos,
AXIONS
Upton,
G. Ruoso,(‘)and
of Physics of Rochester,
NY 11973
Y.K.
and Astronomy Rochester,
NY 14627
F.A. Nezrick Fermi National
Semertzidis(‘)
Accelerator
P.O. Box 500, Batavia,
Laboratory IL 60510
We have searched for a flux of axions produced to x-rays
in a static
magnetic
increase in the rate of x-rays
field.
detected
in the sun by exploiting
The signature in a magnetic
of a solar axion telescope
From the absence of such a signal we set a 3a limit
to two photons
goY-, = (l/M)
eV.
PACS numbers:
18.80.Am,
18.80.Gt
2
provided
flux
would
be an
when the sun passes within
its acceptance.
< 3.9 x 10-O GeV-‘,
their conversion
on the axion
the axion
mass m,
coupling < 0.11
Current
theories
or pseudoscalar broken
of the elementary
particles.
and are referred
has received is broken
much
[2].
These arise naturally
attention
thought
to explain
the energy
scale of the weak interactions,
has been experimentally
related
to the symmetry
z = m,/md
The axion expressed
couples
the P-Q symmetry
excluded
breaking
N 0.56, m,
symmetry which
interactions,
was
occurs at
of axions
in this
breaking
that gives rise to the sxion
occurs
in the range of 10’ - 10’s GeV. The mass, m,,
of the axion
is
scale fa through
- 3.7 x
10e2 GeV’
being the mass of the x0 and f-
to two photons
through
a triangle
the pion decay constant.
anomaly,
and the coupling
can be
as
Here E and N are respectively symmetry
and a = l/137
Axions
by the cooling
3 $
is the fine structure to electrons
and their relative
constant through
coupling
anomalies
which
a two photon
the axion luminosity with the apparent
do not directly
vertex
an eeo vertex
is excluded
couple to leptons,
[6]. They can still be produced
is less than the corresponding age of the sun. Such axions,
of the sun through
the Primakoff
photon
provide
a very efficient
by many orders of magnitude SN1987A
interact
[4,5]. However,
with matter
in the solar interior, luminosity
primarily provided
so as to not conflict
if they exist, must be produced effect as indicated
3
of the Peccei-Quinn
141.
ratea of the sun, the red giants and the supernova
axions”,
in the interior
-1.95)
the color and electromagnetic
that couple ,&rectly
energy loss mechanism
through
effects in strong
breaking,
one that
[3].
goT7 = +(E/N 0
“hadronic
is spontaneously
Of such particles,
f,, - 250 GeV. The existence
NG m.f.= -m,fr 1+s with
bosons [l].
that
[4] that the symmetry
energies,
of low msss scalar
when a global symmetry
the absence of CP violating
It is now believed
the existence
is the axion, which emerges when the Peccei-Quinn
It wss originally
at much higher
predict
to as Nambu-Goldstone
introduced
region
particles
af;undantly
in Fig. la, the rate being
to Me’.
proportional to photons
Figure
lb shows the inverse
in the presence of an external
The spectrum
of the axions
process by which
ruions
field.
emitted
by the sun has been published
[7] and is shown
in Fig. 2a where the rate refers to the axion flux at the surface of the earth. are produced
by blackbody
the few keV range.
radiation
The total
axion luminosity
where La = 3.8 x 10 rs Watts is the photon in our range of sensitivity,
Solar axions can be detected x-rays
is
the length
of the magnetic
where L is the length
(“‘~)*Watts luminosity
of the sun and the integrated
by the inverse process, namely
process is coherent
in
axion
2.8 - 8.8 keV, is
in the presence of a magnetic
The conversion
Since axions
at the center of the sun, their energy is typically
L, = 1.7 x 10-3Lo
luminosity
are converted
field transverse
to their
direction
when the axion and photon
field region 191; in that
of propagation
fields remain
case the conversion
field and B its strength.
of the magnetic
by their reconversion
into [8].
in phase over
probability
is given
In this experiment
.L = 180
cm and B = 2.2 T. The coherence
For our detector However, with
condition
requires
(L = 180 cm, w N 3 keV) the inequality
coherence
can be maintained
a low 2 gas such as helium.
velocity
of the x-ray field is reduced
for higher
dispersion
region is 6lled
of x-rays
the phase
to [lo]
k = ~(1 - w;/2w*) 4
for m. < 0.05 eV.
masses if the conversion
Because of the negative according
(6) is satisfied
(7)
where
U$ = 4an.ssc*
4.1 x 10”
rad/s
is the plasma
an iron core dipole
setting
sun.
which
consisted
magnet
which
with
of a six-inch aperture
was oriented
This provided
with a 2 x 10 cm2 window.
The window
The proportional
The proportional matic x-ray
chamber
in our detector. The detector amplifier
chamber
to disk.
Events
was operated
to the sun.
proportional
with
of the
every day during Attached
chamber
mylar,
[12]
served az one
a PlO (Argon’with
10%
with an ‘sFe source which emits a monochro no differential
the window
was slightly
= 20%.
However,
deformed
and the
this condi-
of Fig. 2a with the energy loss in the window
the expected
x-ray spectrum
by a charge sensitive
was analyzed
The background spectrum
were selected between match
by a LeCroy
386 computer
and the time
8.8 keV and is a reasonable
to a FWHM
window,
from axion conversions
in Fig. 2c.
an IBM/PC
the expected
pressure on the thin
The 5.9 keV line is shown in Fig. 2b under
to obtain
whose output
proportional
directly
which was 0.0005 inch thick
was at vacuum,
signals were collected
through
15 minutes
pointed
at 6 keV corresponds
This is displayed
was acquired
along the azimuth
the sun was an x-ray
the axion spectrum
and the effects of resolution
rate.
region
was calibrated
broader.
We have convolved
3a indicates
of approximately
chamber
resolution
peak became significantly
written
by 6 inches high and 72
line of energy E = 5.9 keV. With
when one side of the window
shaping
of 18 inches horizontal
at one atmosphere.
the anode pulse height
tion.
wp =
pipe placed in the gap of
the vacuum
pipe opposite
gas mixture
diameter
so that its long axis pointed
to the end of the evacuated
Methane)
gas at 1 atmosphere,
vacuum
a time window
the line of sight through
of the cathodes.
For helium
- 0.3 eV.
The axion converter
inches long [ll]
frequency.
of arrival.
spectrum
ADC.
the pulse height
The data was analyzed
is shown in Fig.
on-line
by a Data
from the and also
3a; the dashed curve in Fig.
axions equaled
250 and 850; this corresponds
to the bulk of the expected 5
followed
2259B CAMAC
which recorded
if the rate of converted channels
preamplifier,
axion
the background to 2% < E,
2.55 x 10’ GeV(99.7%C.L.) 6
form.
< 0.11 eV
lower limits
Our results axions
do not reach the sensitivity
since the coherence
accessible
condition
to 0.11 eV while
lines indicated considered
models”
to apply more generally
of solar Primakoff Although
production
this
solar model
result
from considerations
However,
it is an improvement
and longer
can improve
To place this result to two photons, experiments
in context
1121, microwave
decay experiments of the red giants ga-,-, implied
The result
reported
here should
cavity
by Eqs.
(1,2);
experiment,
we show in Fig.
[4,5].
models
excluded
a
M > 2.55
significant
line corresponding improves,
4 the limits
this presumes
program
Brookhaven
and in particular
up the experiment.
However
will encompass
National
Laboratory
Dave Dayton
the coupling
as the sensitivity the predicted
This work was supported
search
coupling
of the sun,
between
m, and
C = (E/N
< 20 eV. Our result sensitivity
-
for these has
to reach the
of the solar experiment
region of the hadronic
for its continuing
laser
(171 and particle
parameter
support
for their invaluable
in part by the U.S. Dept.
7
[15].
We again note that
to a mass m.
and Al Pendzick
of field
experiments:
from the luminosity
of this space but has inadaquate
to the axion models. window
by other
telescope
deduced
that
modifications
on the axion
The heavy line is the relation
10s GeV corresponds
fraction
the detection
We thank
x
over the limits’ that have
order of magnitude
1.95) = (8/3 - 1.95) = 0.72 (see Ref. [4] f or more details). axion
rate (see Fq.(3)).
of the day and using a higher
mass obtained [lS],
on the
on M is at the level
The limit
on M by another
experiments
it depends
[14]. It is clear that
a larger fraction
of axion
the requirements
and thus its cooling
experiments
then be
in our detector.
spectrum.
[3]. We also show the limits and of SN1987A
bosons satisfying
two orders of magnitude
the limit
as a function
g.v7,
lead to the diagonal
in a laboratory
terrestrial
mass range
couplings
conversion
of the expected
to track the sun during
magnet
4.
the axion
axion
to Nambu-Goldstone
of nearly
the presence of hadronic
(6) and (7) limits
of the solar luminosity
on M by purely
this apparatus
in Fig.
was obtained
expected
to determine
and DFSZ[13]
and coherent
for the prediction
been placed
of Eqs.
hadronic
by “sxion
required
axion.
of this research help% of Energy
setting under
contracts
DEAC02-76ER13065,DE-AC02-76CH00016,and
DE-AC02-76CH03000.
ca) Present
address:
Department
of Physics,
University
of Western
Ontario,
London,
ON
N6A 3K7, Canada cb) Present
Address:Dipartimento
I-35106
Padova,
(‘1 Present
address:
di Fisica “Galileo
Gahlei”
dell’ Universitir
di Padova,
Italy Physics
Department,
Brookhaven
National
Laboratory,
Upton,
NY
11973
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[5] C. FLatTelt, Physics [6] J.E. Kim,
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166,
493 (1980). [7] K. Van Bibber
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G. Raffelt,
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61, 1415 (1983); 9
Phys.
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61, 783 (1988).
Dg3,
[9] G. melt
and L. Stodolsky,
(101 J.D. Jackson,
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p. 315, second edition,
Electrodynamics”,
John Wiley
and
sons ed., 1975. [ll]
G.T. Danby,
AGS Internal
(121 G.C. Smith,
Nuclear
[13] M. Dine, W. Fischler nitsky,
Sov. J. Nucl.
114) Y. Semertzidis of Rochester
1151 Such an experiment (private
[16] S. DePanfilis D40,3153
Instruments
Phys.
Dee 26 (1961).
and Methods
31,260
No. UR-1248
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222,230 Lett.
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104B,
199 (1981);
A. R. Zbit-
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is in progress at the Institute
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10
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Rev.
Figure
Cautions
Fig 1 (a) Axion
production
by the Primakoff
effect.
(b) Axion
conversion
to a photon-by
the same process. Fig 2 (a) The calculated for M
differential
= 10’ GeV (from
line under the operating height
spectrum
corrected
ref.
for window
shape if the converted
5).
(distorted
for converted
Fig 3 (a) The background
spectrum axion
of axions
reaching
(b) Pulse height window)
the surface of the earth
spectrum
conditions
and convolved in the detector.
with
(c) The pulse
in (a) of the figure is
the experimental
resolution.
The dashed curve shows the expected
rate equals the background &s a function
of the 5.9 keV Fe5s
of the detector.
solar axions when the spectrum
absorption
2.8 < E, < 8.8 keV plotted data.
spectrum
rate.
(b) The event rate for
of time every 30 seconds for the vacuum
The dashed curve shows the expected
solar axion
signal if that
rate reaches a
peak value of 2 Hz. The solid line is a best fit to the data and shows no enhancement at the sunset time. Fig. 4 The limits
on Nambu-Goldstone
several experiments.
coupling
to two photons
Also shown are the astrophysical
axion models encompasses
the predictions
models.
11
vs. the boson mass from
limits.
of the “hadronic”
The solid line labeled [6] and DFSZ
[13] axion
TABLE He pressures
I. Axion
mass ranges, fit parameters,
and 3a level limits
on M for the three
used in the experiment.
x2 d.o.f.
M(GeV)(3a
limit)
Pressure( Torr)
m.(eV
&(Hz)
0
< 0.050
2.127 f 0.037
-0.036
4~ 0.055
0.67
2.79 x 10s
55
0.050 - 0.086
2.087 rt 0.055
-0.037
3~ 0.074
1.11
2.55 x 10’
100
0.086 - 0.110
1.970 f 0.034
-0.073
f 0.060
1.10
2.92 x 10s
R,(Hz)
12
I r-
X
7
8 I- ’ I I
1 I I I I I I
7
+
+ +
+
6
+
+++++
+
+
+
+* +
x (IO’ GeV / M )* + +
+
+ +
+
3t?
I I I
++
+
5
2
++
I I I
+ +
+
+
+
+
+ I- +
0
2
4 6 Axion energy (keV) Figure
2a
8
IO
T
-
I I I I
I I I I z is 4
I 1I 1 z z4 S~UflO3 S~UflO3
0
z tis
0
i +j i ++ +
-t
+
++ +++ +++ +
++ + +
+
+
++
+ +
+
+ +
+
l,,,,l~,,,l,,,,l,,,,l,,,,l,,,,l,,,~ z 03
E
0 z
z
g
0 8
z
8 7
0
‘i / ‘I I
\. \
I
800 1 cn E
2 0
600 400
‘\ ?
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I.\ \\ 1\ ‘\‘\
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600 800 1000120014001600. Channel# Figure
3a
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it ‘S= ti; 2 ci
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(oas / swno3) aleu
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