-
Direct neutrino-mass measurement based on 259 days of KATRIN data
Authors:
M. Aker,
D. Batzler,
A. Beglarian,
J. Behrens,
J. Beisenkötter,
M. Biassoni,
B. Bieringer,
Y. Biondi,
F. Block,
S. Bobien,
M. Böttcher,
B. Bornschein,
L. Bornschein,
T. S. Caldwell,
M. Carminati,
A. Chatrabhuti,
S. Chilingaryan,
B. A. Daniel,
K. Debowski,
M. Descher,
D. Díaz Barrero,
P. J. Doe,
O. Dragoun,
G. Drexlin,
F. Edzards
, et al. (124 additional authors not shown)
Abstract:
The fact that neutrinos carry a non-vanishing rest mass is evidence of physics beyond the Standard Model of elementary particles. Their absolute mass bears important relevance from particle physics to cosmology. In this work, we report on the search for the effective electron antineutrino mass with the KATRIN experiment. KATRIN performs precision spectroscopy of the tritium $β$-decay close to the…
▽ More
The fact that neutrinos carry a non-vanishing rest mass is evidence of physics beyond the Standard Model of elementary particles. Their absolute mass bears important relevance from particle physics to cosmology. In this work, we report on the search for the effective electron antineutrino mass with the KATRIN experiment. KATRIN performs precision spectroscopy of the tritium $β$-decay close to the kinematic endpoint. Based on the first five neutrino-mass measurement campaigns, we derive a best-fit value of $m_ν^{2} = {-0.14^{+0.13}_{-0.15}}~\mathrm{eV^2}$, resulting in an upper limit of $m_ν< {0.45}~\mathrm{eV}$ at 90 % confidence level. With six times the statistics of previous data sets, amounting to 36 million electrons collected in 259 measurement days, a substantial reduction of the background level and improved systematic uncertainties, this result tightens KATRIN's previous bound by a factor of almost two.
△ Less
Submitted 19 June, 2024;
originally announced June 2024.
-
Search for keV-scale Sterile Neutrinos with first KATRIN Data
Authors:
M. Aker,
D. Batzler,
A. Beglarian,
J. Behrens,
A. Berlev,
U. Besserer,
B. Bieringer,
F. Block,
S. Bobien,
B. Bornschein,
L. Bornschein,
M. Böttcher,
T. Brunst,
T. S. Caldwell,
R. M. D. Carney,
S. Chilingaryan,
W. Choi,
K. Debowski,
M. Descher,
D. Díaz Barrero,
P. J. Doe,
O. Dragoun,
G. Drexlin,
F. Edzards,
K. Eitel
, et al. (106 additional authors not shown)
Abstract:
In this work we present a keV-scale sterile-neutrino search with the first tritium data of the KATRIN experiment, acquired in the commissioning run in 2018. KATRIN performs a spectroscopic measurement of the tritium $β$-decay spectrum with the main goal of directly determining the effective electron anti-neutrino mass. During this commissioning phase a lower tritium activity facilitated the search…
▽ More
In this work we present a keV-scale sterile-neutrino search with the first tritium data of the KATRIN experiment, acquired in the commissioning run in 2018. KATRIN performs a spectroscopic measurement of the tritium $β$-decay spectrum with the main goal of directly determining the effective electron anti-neutrino mass. During this commissioning phase a lower tritium activity facilitated the search for sterile neutrinos with a mass of up to $1.6\, \mathrm{keV}$. We do not find a signal and set an exclusion limit on the sterile-to-active mixing amplitude of down to $\sin^2θ< 5\cdot10^{-4}$ ($95\,\%$ C.L.), improving current laboratory-based bounds in the sterile-neutrino mass range between 0.1 and $1.0\, \mathrm{keV}$.
△ Less
Submitted 13 July, 2022;
originally announced July 2022.
-
Search for Lorentz-Invariance Violation with the first KATRIN data
Authors:
M. Aker,
D. Batzler,
A. Beglarian,
J. Behrens,
A. Berlev,
U. Besserer,
B. Bieringer,
F. Block,
S. Bobien,
B. Bornschein,
L. Bornschein,
M. Böttcher,
T. Brunst,
T. S. Caldwell,
R. M. D. Carney,
S. Chilingaryan,
W. Choi,
K. Debowski,
M. Deffert,
M. Descher,
D. Díaz Barrero,
P. J. Doe,
O. Dragoun,
G. Drexlin,
F. Edzards
, et al. (108 additional authors not shown)
Abstract:
Some extensions of the Standard Model of Particle Physics allow for Lorentz invariance and Charge-Parity-Time (CPT)-invariance violations. In the neutrino sector strong constraints have been set by neutrino-oscillation and time-of-flight experiments. However, some Lorentz-invariance-violating parameters are not accessible via these probes. In this work, we focus on the parameters…
▽ More
Some extensions of the Standard Model of Particle Physics allow for Lorentz invariance and Charge-Parity-Time (CPT)-invariance violations. In the neutrino sector strong constraints have been set by neutrino-oscillation and time-of-flight experiments. However, some Lorentz-invariance-violating parameters are not accessible via these probes. In this work, we focus on the parameters $(a_{\text{of}}^{(3)})_{00}$, $(a_{\text{of}}^{(3)})_{10}$ and $(a_{\text{of}}^{(3)})_{11}$ which would manifest themselves in a non-isotropic beta-decaying source as a sidereal oscillation and an overall shift of the spectral endpoint. Based on the data of the first scientific run of the KATRIN experiment, we set the first limit on $\left|(a_{\text{of}}^{(3)})_{11}\right|$ of $< 3.7\cdot10^{-6}$ GeV at 90\% confidence level. Moreover, we derive new constraints on $(a_{\text{of}}^{(3)})_{00}$ and $(a_{\text{of}}^{(3)})_{10}$.
△ Less
Submitted 13 July, 2022;
originally announced July 2022.
-
KATRIN: Status and Prospects for the Neutrino Mass and Beyond
Authors:
M. Aker,
M. Balzer,
D. Batzler,
A. Beglarian,
J. Behrens,
A. Berlev,
U. Besserer,
M. Biassoni,
B. Bieringer,
F. Block,
S. Bobien,
L. Bombelli,
D. Bormann,
B. Bornschein,
L. Bornschein,
M. Böttcher,
C. Brofferio,
C. Bruch,
T. Brunst,
T. S. Caldwell,
M. Carminati,
R. M. D. Carney,
S. Chilingaryan,
W. Choi,
O. Cremonesi
, et al. (137 additional authors not shown)
Abstract:
The Karlsruhe Tritium Neutrino (KATRIN) experiment is designed to measure a high-precision integral spectrum of the endpoint region of T2 beta decay, with the primary goal of probing the absolute mass scale of the neutrino. After a first tritium commissioning campaign in 2018, the experiment has been regularly running since 2019, and in its first two measurement campaigns has already achieved a su…
▽ More
The Karlsruhe Tritium Neutrino (KATRIN) experiment is designed to measure a high-precision integral spectrum of the endpoint region of T2 beta decay, with the primary goal of probing the absolute mass scale of the neutrino. After a first tritium commissioning campaign in 2018, the experiment has been regularly running since 2019, and in its first two measurement campaigns has already achieved a sub-eV sensitivity. After 1000 days of data-taking, KATRIN's design sensitivity is 0.2 eV at the 90% confidence level. In this white paper we describe the current status of KATRIN; explore prospects for measuring the neutrino mass and other physics observables, including sterile neutrinos and other beyond-Standard-Model hypotheses; and discuss research-and-development projects that may further improve the KATRIN sensitivity.
△ Less
Submitted 16 June, 2023; v1 submitted 15 March, 2022;
originally announced March 2022.
-
New Constraint on the Local Relic Neutrino Background Overdensity with the First KATRIN Data Runs
Authors:
M. Aker,
D. Batzler,
A. Beglarian,
J. Behrens,
A. Berlev,
U. Besserer,
B. Bieringer,
F. Block,
S. Bobien,
B. Bornschein,
L. Bornschein,
M. Böttcher,
T. Brunst,
T. S. Caldwell,
R. M. D. Carney,
S. Chilingaryan,
W. Choi,
K. Debowski,
M. Descher,
D. Díaz Barrero,
P. J. Doe,
O. Dragoun,
G. Drexlin,
F. Edzards,
K. Eitel
, et al. (107 additional authors not shown)
Abstract:
We report on the direct cosmic relic neutrino background search from the first two science runs of the KATRIN experiment in 2019. Beta-decay electrons from a high-purity molecular tritium gas source are analyzed by a high-resolution MAC-E filter around the kinematic endpoint at 18.57 keV. The analysis is sensitive to a local relic neutrino overdensity of 9.7e10 (1.1e11) at a 90% (95%) confidence l…
▽ More
We report on the direct cosmic relic neutrino background search from the first two science runs of the KATRIN experiment in 2019. Beta-decay electrons from a high-purity molecular tritium gas source are analyzed by a high-resolution MAC-E filter around the kinematic endpoint at 18.57 keV. The analysis is sensitive to a local relic neutrino overdensity of 9.7e10 (1.1e11) at a 90% (95%) confidence level. A fit of the integrated electron spectrum over a narrow interval around the kinematic endpoint accounting for relic neutrino captures in the Tritium source reveals no significant overdensity. This work improves the results obtained by the previous kinematic neutrino mass experiments at Los Alamos and Troitsk. We furthermore update the projected final sensitivity of the KATRIN experiment to <1e10 at 90% confidence level, by relying on updated operational conditions.
△ Less
Submitted 9 February, 2022;
originally announced February 2022.
-
The Radioactive Nuclei $^{\textbf{26}}$Al and $^{\textbf{60}}$Fe in the Cosmos and in the Solar System
Authors:
Roland Diehl,
Maria Lugaro,
Alexander Heger,
Andre Sieverding,
Xiaodong Tang,
KuoAng Li,
Ertao Li,
Carolyn L. Doherty,
Martin G. H. Krause,
Anton Wallner,
Nikos Prantzos,
Hannah E. Brinkman,
Jaqueline W. den Hartogh,
Benjamin Wehmeyer,
Andrés Yagüe López,
Moritz M. M. Pleintinger,
Projjval Banerjee,
Wei Wang
Abstract:
The cosmic evolution of the chemical elements from the Big Bang to the present time is driven by nuclear fusion reactions inside stars and stellar explosions. A cycle of matter recurrently re-processes metal-enriched stellar ejecta into the next generation of stars. The study of cosmic nucleosynthesis and of this matter cycle requires the understanding of the physics of nuclear reactions, of the c…
▽ More
The cosmic evolution of the chemical elements from the Big Bang to the present time is driven by nuclear fusion reactions inside stars and stellar explosions. A cycle of matter recurrently re-processes metal-enriched stellar ejecta into the next generation of stars. The study of cosmic nucleosynthesis and of this matter cycle requires the understanding of the physics of nuclear reactions, of the conditions at which the nuclear reactions are activated inside the stars and stellar explosions, of the stellar ejection mechanisms through winds and explosions, and of the transport of the ejecta towards the next cycle, from hot plasma to cold, star-forming gas. Due to the long timescales of stellar evolution, and because of the infrequent occurrence of stellar explosions, observational studies are challenging. Due to their radioactive lifetime of million years, the 26Al and 60Fe isotopes are suitable to characterise simultaneously the processes of nuclear fusion reactions and of interstellar transport. We describe and discuss the nuclear reactions involved in the production and destruction of 26Al and 60Fe, the key characteristics of the stellar sites of their nucleosynthesis and their interstellar journey after ejection from the nucleosynthesis sites. We connect the theoretical astrophysical aspects to the variety of astronomical messengers, from stardust and cosmic-ray composition measurements, through observation of gamma rays produced by radioactivity, to material deposited in deep-sea ocean crusts and to the inferred composition of the first solids that have formed in the Solar System. We show that considering measurements of the isotopic ratio of 26Al to 60Fe eliminate some of the unknowns when interpreting astronomical results, and discuss the lessons learned from these two isotopes on cosmic chemical evolution.
△ Less
Submitted 5 October, 2021; v1 submitted 17 September, 2021;
originally announced September 2021.
-
First direct neutrino-mass measurement with sub-eV sensitivity
Authors:
M. Aker,
A. Beglarian,
J. Behrens,
A. Berlev,
U. Besserer,
B. Bieringer,
F. Block,
B. Bornschein,
L. Bornschein,
M. Böttcher,
T. Brunst,
T. S. Caldwell,
R. M. D. Carney,
L. La Cascio,
S. Chilingaryan,
W. Choi,
K. Debowski,
M. Deffert,
M. Descher,
D. Díaz Barrero,
P. J. Doe,
O. Dragoun,
G. Drexlin,
K. Eitel,
E. Ellinger
, et al. (103 additional authors not shown)
Abstract:
We report the results of the second measurement campaign of the Karlsruhe Tritium Neutrino (KATRIN) experiment. KATRIN probes the effective electron anti-neutrino mass, $m_ν$, via a high-precision measurement of the tritium $β$-decay spectrum close to its endpoint at $18.6\,\mathrm{keV}$. In the second physics run presented here, the source activity was increased by a factor of 3.8 and the backgro…
▽ More
We report the results of the second measurement campaign of the Karlsruhe Tritium Neutrino (KATRIN) experiment. KATRIN probes the effective electron anti-neutrino mass, $m_ν$, via a high-precision measurement of the tritium $β$-decay spectrum close to its endpoint at $18.6\,\mathrm{keV}$. In the second physics run presented here, the source activity was increased by a factor of 3.8 and the background was reduced by $25\,\%$ with respect to the first campaign. A sensitivity on $m_ν$ of $0.7\,\mathrm{eV/c^2}$ at $90\,\%$ confidence level (CL) was reached. This is the first sub-eV sensitivity from a direct neutrino-mass experiment. The best fit to the spectral data yields $m_ν^2 = (0.26\pm0.34)\,\mathrm{eV^4/c^4}$, resulting in an upper limit of $m_ν<0.9\,\mathrm{eV/c^2}$ ($90\,\%$ CL). By combining this result with the first neutrino mass campaign, we find an upper limit of $m_ν<0.8\,\mathrm{eV/c^2}$ ($90\,\%$ CL).
△ Less
Submitted 18 May, 2021;
originally announced May 2021.
-
Analysis methods for the first KATRIN neutrino-mass measurement
Authors:
M. Aker,
K. Altenmüller,
A. Beglarian,
J. Behrens,
A. Berlev,
U. Besserer,
B. Bieringer,
K. Blaum,
F. Block,
B. Bornschein,
L. Bornschein,
M. Böttcher,
T. Brunst,
T. S. Caldwell,
L. La Cascio,
S. Chilingaryan,
W. Choi,
D. Díaz Barrero,
K. Debowski,
M. Deffert,
M. Descher,
P. J. Doe,
O. Dragoun,
G. Drexlin,
S. Dyba
, et al. (104 additional authors not shown)
Abstract:
We report on the data set, data handling, and detailed analysis techniques of the first neutrino-mass measurement by the Karlsruhe Tritium Neutrino (KATRIN) experiment, which probes the absolute neutrino-mass scale via the $β$-decay kinematics of molecular tritium. The source is highly pure, cryogenic T$_2$ gas. The $β$ electrons are guided along magnetic field lines toward a high-resolution, inte…
▽ More
We report on the data set, data handling, and detailed analysis techniques of the first neutrino-mass measurement by the Karlsruhe Tritium Neutrino (KATRIN) experiment, which probes the absolute neutrino-mass scale via the $β$-decay kinematics of molecular tritium. The source is highly pure, cryogenic T$_2$ gas. The $β$ electrons are guided along magnetic field lines toward a high-resolution, integrating spectrometer for energy analysis. A silicon detector counts $β$ electrons above the energy threshold of the spectrometer, so that a scan of the thresholds produces a precise measurement of the high-energy spectral tail. After detailed theoretical studies, simulations, and commissioning measurements, extending from the molecular final-state distribution to inelastic scattering in the source to subtleties of the electromagnetic fields, our independent, blind analyses allow us to set an upper limit of 1.1 eV on the neutrino-mass scale at a 90\% confidence level. This first result, based on a few weeks of running at a reduced source intensity and dominated by statistical uncertainty, improves on prior limits by nearly a factor of two. This result establishes an analysis framework for future KATRIN measurements, and provides important input to both particle theory and cosmology.
△ Less
Submitted 12 May, 2021; v1 submitted 13 January, 2021;
originally announced January 2021.
-
Bound on 3+1 active-sterile neutrino mixing from the first four-week science run of KATRIN
Authors:
M. Aker,
K. Altenmueller,
A. Beglarian,
J. Behrens,
A. Berlev,
U. Besserer,
B. Bieringer,
K. Blaum,
F. Block,
B. Bornschein,
L. Bornschein,
M. Boettcher,
T. Brunst,
T. S. Caldwell,
L. La Cascio,
S. Chilingaryan,
W. Choi,
D. Diaz Barrero,
K. Debowski,
M. Deffert,
M. Descher,
P. J. Doe,
O. Dragoun,
G. Drexlin,
S. Dyba
, et al. (104 additional authors not shown)
Abstract:
We report on the light sterile neutrino search from the first four-week science run of the KATRIN experiment in~2019. Beta-decay electrons from a high-purity gaseous molecular tritium source are analyzed by a high-resolution MAC-E filter down to 40 eV below the endpoint at 18.57 keV. We consider the framework with three active neutrinos and one sterile neutrino of mass $m_{4}$. The analysis is sen…
▽ More
We report on the light sterile neutrino search from the first four-week science run of the KATRIN experiment in~2019. Beta-decay electrons from a high-purity gaseous molecular tritium source are analyzed by a high-resolution MAC-E filter down to 40 eV below the endpoint at 18.57 keV. We consider the framework with three active neutrinos and one sterile neutrino of mass $m_{4}$. The analysis is sensitive to a fourth mass state $m^2_{4} \lesssim$ 1000 eV$^2$ and to active-to-sterile neutrino mixing down to $|U_{e4}|^2 \gtrsim 2\cdot10^{-2}$. No significant spectral distortion is observed and exclusion bounds on the sterile mass and mixing are reported. These new limits supersede the Mainz results and improve the Troitsk bound for $m^2_{4} <$ 30 eV$^2$. The reactor and gallium anomalies are constrained for $ 100 < Δ{m}^2_{41} < 1000$ eV$^2$.
△ Less
Submitted 10 November, 2020;
originally announced November 2020.
-
First operation of the KATRIN experiment with tritium
Authors:
M. Aker,
K. Altenmüller,
M. Arenz,
W. -J. Baek,
J. Barrett,
A. Beglarian,
J. Behrens,
A. Berlev,
U. Besserer,
K. Blaum,
F. Block,
S. Bobien,
B. Bornschein,
L. Bornschein,
H. Bouquet,
T. Brunst,
T. S. Caldwell,
S. Chilingaryan,
W. Choi,
K. Debowski,
M. Deffert,
M. Descher,
D. Díaz Barrero,
P. J. Doe,
O. Dragoun
, et al. (146 additional authors not shown)
Abstract:
The determination of the neutrino mass is one of the major challenges in astroparticle physics today. Direct neutrino mass experiments, based solely on the kinematics of beta-decay, provide a largely model-independent probe to the neutrino mass scale. The Karlsruhe Tritium Neutrino (KATRIN) experiment is designed to directly measure the effective electron antineutrino mass with a sensitivity of 0.…
▽ More
The determination of the neutrino mass is one of the major challenges in astroparticle physics today. Direct neutrino mass experiments, based solely on the kinematics of beta-decay, provide a largely model-independent probe to the neutrino mass scale. The Karlsruhe Tritium Neutrino (KATRIN) experiment is designed to directly measure the effective electron antineutrino mass with a sensitivity of 0.2 eV 90% CL. In this work we report on the first operation of KATRIN with tritium which took place in 2018. During this commissioning phase of the tritium circulation system, excellent agreement of the theoretical prediction with the recorded spectra was found and stable conditions over a time period of 13 days could be established. These results are an essential prerequisite for the subsequent neutrino mass measurements with KATRIN in 2019.
△ Less
Submitted 13 September, 2019;
originally announced September 2019.
-
An improved upper limit on the neutrino mass from a direct kinematic method by KATRIN
Authors:
M. Aker,
K. Altenmüller,
M. Arenz,
M. Babutzka,
J. Barrett,
S. Bauer,
M. Beck,
A. Beglarian,
J. Behrens,
T. Bergmann,
U. Besserer,
K. Blaum,
F. Block,
S. Bobien,
K. Bokeloh,
J. Bonn,
B. Bornschein,
L. Bornschein,
H. Bouquet,
T. Brunst,
T. S. Caldwell,
L. La Cascio,
S. Chilingaryan,
W. Choi,
T. J. Corona
, et al. (184 additional authors not shown)
Abstract:
We report on the neutrino mass measurement result from the first four-week science run of the Karlsruhe Tritium Neutrino experiment KATRIN in spring 2019. Beta-decay electrons from a high-purity gaseous molecular tritium source are energy analyzed by a high-resolution MAC-E filter. A fit of the integrated electron spectrum over a narrow interval around the kinematic endpoint at 18.57 keV gives an…
▽ More
We report on the neutrino mass measurement result from the first four-week science run of the Karlsruhe Tritium Neutrino experiment KATRIN in spring 2019. Beta-decay electrons from a high-purity gaseous molecular tritium source are energy analyzed by a high-resolution MAC-E filter. A fit of the integrated electron spectrum over a narrow interval around the kinematic endpoint at 18.57 keV gives an effective neutrino mass square value of $(-1.0^{+0.9}_{-1.1})$ eV$^2$. From this we derive an upper limit of 1.1 eV (90$\%$ confidence level) on the absolute mass scale of neutrinos. This value coincides with the KATRIN sensitivity. It improves upon previous mass limits from kinematic measurements by almost a factor of two and provides model-independent input to cosmological studies of structure formation.
△ Less
Submitted 13 September, 2019;
originally announced September 2019.
-
New method for a continuous determination of the spin tune in storage rings and implications for precision experiments
Authors:
D. Eversmann,
V. Hejny,
F. Hinder,
A. Kacharava,
J. Pretz,
F. Rathmann,
M. Rosenthal,
F. Trinkel,
S. Andrianov,
W. Augustyniak,
Z. Bagdasarian,
M. Bai,
W. Bernreuther,
S. Bertelli,
M. Berz,
J. Bsaisou,
S. Chekmenev,
D. Chiladze,
G. Ciullo,
M. Contalbrigo,
J. de Vries,
S. Dymov,
R. Engels,
F. M. Esser,
O. Felden
, et al. (76 additional authors not shown)
Abstract:
A new method to determine the spin tune is described and tested. In an ideal planar magnetic ring, the spin tune - defined as the number of spin precessions per turn - is given by $ν_s = γG$ (gamma is the Lorentz factor, $G$ the magnetic anomaly). For 970 MeV/c deuterons coherently precessing with a frequency of ~120 kHz in the Cooler Synchrotron COSY, the spin tune is deduced from the up-down asy…
▽ More
A new method to determine the spin tune is described and tested. In an ideal planar magnetic ring, the spin tune - defined as the number of spin precessions per turn - is given by $ν_s = γG$ (gamma is the Lorentz factor, $G$ the magnetic anomaly). For 970 MeV/c deuterons coherently precessing with a frequency of ~120 kHz in the Cooler Synchrotron COSY, the spin tune is deduced from the up-down asymmetry of deuteron carbon scattering. In a time interval of 2.6 s, the spin tune was determined with a precision of the order $10^{-8}$, and to $1 \cdot 10^{-10}$ for a continuous 100 s accelerator cycle. This renders the presented method a new precision tool for accelerator physics: controlling the spin motion of particles to high precision is mandatory, in particular, for the measurement of electric dipole moments of charged particles in a storage ring.
△ Less
Submitted 21 March, 2017; v1 submitted 2 April, 2015;
originally announced April 2015.
-
Measurement of Spin Correlation Parameters A$_{NN}$, A$_{SS}$, and A_${SL}$ at 2.1 GeV in Proton-Proton Elastic Scattering
Authors:
F. Bauer,
J. Bisplinghoff,
K. Büßer,
M. Busch,
T. Colberg,
L. Demirörs,
C. Dahl,
P. D. Eversheim,
O. Eyser,
O. Felden,
R. Gebel,
J. Greiff,
R. Groß-Hardt,
F. Hinterberger,
R. Jahn,
E. Jonas,
H. Krause,
C. Lehmann,
J. Lindlein,
R. Maier,
A. Meinerzhagen,
C. Pauly,
D. Prasuhn,
H. Rohdjeß,
D. Rosendaal
, et al. (7 additional authors not shown)
Abstract:
At the Cooler Synchrotron COSY/Jülich spin correlation parameters in elastic proton-proton (pp) scattering have been measured with a 2.11 GeV polarized proton beam and a polarized hydrogen atomic beam target. We report results for A$_{NN}$, A$_{SS}$, and A_${SL}$ for c.m. scattering angles between 30$^o$ and 90$^o$. Our data on A$_{SS}$ -- the first measurement of this observable above 800 MeV -…
▽ More
At the Cooler Synchrotron COSY/Jülich spin correlation parameters in elastic proton-proton (pp) scattering have been measured with a 2.11 GeV polarized proton beam and a polarized hydrogen atomic beam target. We report results for A$_{NN}$, A$_{SS}$, and A_${SL}$ for c.m. scattering angles between 30$^o$ and 90$^o$. Our data on A$_{SS}$ -- the first measurement of this observable above 800 MeV -- clearly disagrees with predictions of available of pp scattering phase shift solutions while A$_{NN}$ and A_${SL}$ are reproduced reasonably well. We show that in the direct reconstruction of the scattering amplitudes from the body of available pp elastic scattering data at 2.1 GeV the number of possible solutions is considerably reduced.
△ Less
Submitted 27 February, 2003; v1 submitted 6 September, 2002;
originally announced September 2002.