CDHS experiment
CDHS was a neutrino experiment at CERN taking data from 1976 until 1984. The experiment was officially referred to as WA1. CDHS was a collaboration of groups from
Experimental setup
The core of the detector consisted of 19 (later 20) magnetized iron modules. In the spacings between these, drift chambers for track reconstruction were installed. Additionally, plastic scintillators were inserted into the iron. Each iron module therefore served successively as an interaction target, where the neutrinos hit and produced hadron showers, a calorimeter that measured those hadrons' energy and a spectrometer, determining the momenta of produced muons via magnetic deflection.[1][2]
At the time of its completion in 1976, the overall detector was 20 m long and weighed approximately 1250 tons.
The experiment was located in CERN's
History
The experiment was first proposed in July 1973 by a group led by Jack Steinberger as a two-piece detector. The front should serve as the neutrino target and hadronic shower detector, the following second part should detect the muon traces.[3] It was planned that the four proposing groups from Saclay, Dortmund, Heidelberg and CERN would contribute with complementary expertise and manpower. For example, Saclay was assigned to be in charge of the drift chambers, whereas CERN should handle the iron core magnets. It were also these four groups that gave the experiment its name: CERN Dortmund Heidelberg Saclay (CDHS). Approximately 30 people should form the final experiment group.[4]
After prolonged discussions with the SPS Committee, that was in charge of approving the proposals and distributing available money, an updated proposal for the new detector was submitted in March 1974. The suggested detector was a modular setup consisting of magnetized iron modules in combination with drift chambers and plastic scintillators.[5] This new proposal was approved by the committee in April 1974. Construction started soon after and was completed in 1976. The experiment's official name was WA1, since it was the first approved experiment at CERN's West Area. The estimated cost of the detector ranged between 6 and 8 million CHF.[3]
In 1979, an upgrade of the experimental setup was proposed.
CDHS took data with neutrinos delivered by the SPS from late 1976 until September 1984.
Results and discoveries
The scientific goal of the CDHS experiment was to study high energy neutrino interactions. When the incoming neutrinos (or antineutrinos) were interacting with the target iron, either charged current (
ν
+ Fe →
μ+
+ anything) or neutral current (
ν
+ Fe →
ν
+ anything) events could be produced.[2]
One of the main objectives of the experiment was to determine the ratio between the neutral and the charged inclusive neutrino
Other measurements regarding the
Results obtained at CDHS provided experimental validation of the
CDHS examined the nucleon structure functions, which enabled scientists to confirm the theory of quantum chromodynamics (QCD).[15][8] This work included the determination of the QCD coupling constant , verification of the quark's (s = 1/2) and gluon's (s = 1) spin, as well as the falsification of both abelian theories of strong interactions and theories based on scalar gluons.[9][15] Additionally, the experiments provided insights into the structure of the
During its last years of operation, the CDHS collaboration engaged in the search for neutrino oscillations. Although this phenomenon could not be confirmed using CERN's large energy neutrino beam, this attempt influenced the following experiments that eventually discovered neutrino oscillations.[18]
External links
References
- ^ a b CERN Document Server: Annual Report 1976 (Experimental Physics Division) Retrieved on 14 August 2018
- ^ .
- ^ a b CERN Document Server: Proposal to study high-energy neutrino interactions at the SPS Retrieved on 13 August 2018
- ^ CERN Document Server: Memorandum following up the proposal Retrieved on 13 August 2018
- ^ CERN Document Server: Memorandum - design and physics of the proposed muon spectrometer Retrieved on 16 August 2018
- ^ CERN Document Server: Request for approval of WA1 improvement programme Retrieved on 14 August 2018
- ^ CERN Document Server: New developments at WA1 (CERN Bulletin Issue No. 7/1982) Retrieved on 14 August 2018
- ^ S2CID 124390593.
- ^ S2CID 121625052.
- ^ a b c CERN Document Server: W. D. Schlatter - Highlights from High Energy Neutrino Experiments at CERN Retrieved on 14 August 2018
- .
- .
- .
- ^ Holder, M.; Knobloch, J.; May, J.; Paar, H. P.; Palazzi, P.; Schlatter, D.; Steinberger, J.; Suter, H.; Wahl, H.; Williams, E. G. H.; Eisele, F.; Geweniger, C.; Kleinknecht, K.; Spahn, G.; Willutzki, H. -J.; Dorth, W.; Dydak, F.; Hepp, V.; Tittel, K.; Wotschack, J.; Bloch, P.; Devaux, B.; Grimm, M.; Maillard, J.; Peyaud, B.; Rander, J.; Savoy-Navarro, A.; Turlay, R.; Navarria, F. L. (1977). "Is There a High-Anomaly in Antineutrino Interactions?". Physical Review Letters. 39 (8): 433–436. .
- ^ a b H. Abramovicz: Tests of QCD and Non-Asymptotically-Free Theories of the Strong Interaction by an Analysis of the Nucleon Structure Functions , and
q
Retrieved on 15 August 2018 - ^ CERN Newsletter of the EP Department: Interview with Philippe Bloch Retrieved on 16 August 2018
- S2CID 120216054.
- ^ F. Dydak et al.: A search for
ν
μ oscillations in the Δ range 0.3–90 Retrieved on 16 August 2018