# UA6 experiment

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Super Proton–Antiproton Synchrotron (SppS) Key SppS Experiments UA1 Underground Area 1 UA2 Underground Area 2 UA4 Underground Area 4 UA5 Underground Area 5 SppS pre-accelerators PS Proton Synchrotron AA Antiproton Accumulator

UA6 experiment at CERN

The **Underground Area 6** (**UA6**), also referred to as PHOTONS, experiment was a [high-energy physics](/source/High-energy_physics) experiment at the [Proton-Antiproton Collider](/source/Proton-Antiproton_Collider) (**SppS**), a modification of the [Super Proton Synchrotron](/source/Super_Proton_Synchrotron) (**SPS**), at [CERN](/source/CERN). The experiment ran from 1984 to 1990, with the purpose of studying inclusive [electromagnetic](/source/Electromagnetism) final states and [lambda](/source/Lambda_baryon) production in proton-[antiproton](/source/Antiproton) and [proton](/source/Proton)-proton interactions.[1][2] Towards the end of its run it focused more on direct-[photon](/source/Photon) and [J/ψ](/source/J%2Fpsi_meson) production.[3] The experiment is complementary to the [UA1](/source/UA1_experiment), [UA2](/source/UA2_experiment) and [CDF](/source/Collider_Detector_at_Fermilab) experiments.[4]

Schematic diagram of the UA6 experiment

UA6 is a [fixed target experiment](/source/Fixed-target_experiment) in which an internal [H2](/source/Hydrogen) cluster [jet](/source/Jet_(particle_physics)) is sent through the [collider](/source/Collider) beams. The [luminosity](/source/Luminosity) is measured with four [silicon detector](/source/Silicon_detector) that count the recoil protons from the [scattering](/source/Scattering).[5] This is followed by a double-arm [spectrometer](/source/Spectrometer), with each arm consisting of five multiword [proportional chambers](/source/Proportional_Chamber) (PCs) spaced behind and in front of a [dipole magnet](/source/Dipole_magnet), an [ionisation chamber](/source/Ionization_chamber), a [transition radiation detector](/source/Transition_radiation_detector), and an [electromagnetic calorimeter](/source/Electromagnetic_calorimeter). The spectrometer is placed on the other side of the jet target for pp collisions.[4] The signals for the [trigger](/source/Trigger_(particle_physics)) decisions are provided by the calorimeter and a hodoscope of seven [scintillation counters](/source/Scintillation_counter) between the first two modules of the calorimeter.[5][6]

Computer room for the UA6 experiment

Throughout the running of UA6 the detector setup was progressively upgraded, resulting in increased available antiproton luminosity, minimised background interactions, and improved trigger logic.[3]

Preliminary results of the experiment showed clear peaks in the data from the two-photon decays of the [π0](/source/Pion) and η mesons.[7] Results from the experiment was used to publish cross sections for π0 and η production, [direct photon](/source/Direct_photon) production, [elastic scattering](/source/Elastic_scattering), and J/ψ production.[2][8][9][10][5]

## See also

- [UA2 experiment](/source/UA2_experiment)

- [List of Super Proton Synchrotron experiments](/source/List_of_Super_Proton_Synchrotron_experiments)

## External links

- [CERN Greybook for UA6](https://greybook.cern.ch/experiment/detail?id=UA6)

## References

1. **[^](#cite_ref-1)** ["Greybook"](https://greybook.cern.ch/experiment/detail?id=UA6). *greybook.cern.ch*. Retrieved 2023-08-04.

1. ^ [***a***](#cite_ref-:0_2-0) [***b***](#cite_ref-:0_2-1) Snow, Gregory R. (1991-08-08). ["A novel triggering system for the UA6 electromagnetic calorimeter"](https://books.google.com/books?id=6ocvDwAAQBAJ&dq=UA6+experiment&pg=PA251). In Para, Adam; Anderson, D. F.; Derrick, M.; Fisk, H. E.; Sazama, Cynthia (eds.). *Calorimetry in High Energy Physics - Proceedings of the International Conference*. #N/A. [ISBN](/source/ISBN_(identifier)) [978-981-4556-54-5](https://en.wikipedia.org/wiki/Special:BookSources/978-981-4556-54-5).

1. ^ [***a***](#cite_ref-:1_3-0) [***b***](#cite_ref-:1_3-1) ["Experimental Studies of Elementary Particle Interactions at High Energy"](https://inis.iaea.org/collection/NCLCollectionStore/_Public/27/032/27032831.pdf) (PDF). *The Rockefeller University*. 31 Mar 1992.

1. ^ [***a***](#cite_ref-:2_4-0) [***b***](#cite_ref-:2_4-1) Snow, Gregory R. (16 Nov 1988). ["Direct Photon Physics From CERN Experiment UA6"](https://cds.cern.ch/record/192866/files/198812057.pdf) (PDF). *VIIth Topical Workshop on Proton–Antiproton Collider Physics, Fermilab, Batavia, Ill., USA, 2–24 June 1988*.

1. ^ [***a***](#cite_ref-:3_5-0) [***b***](#cite_ref-:3_5-1) [***c***](#cite_ref-:3_5-2) Morel, C.; Bernasconi, A.; Breedon, R.E.; Camilleri, L.; Cool, R.L.; Cox, P.T.; [Cushman, P.](/source/Priscilla_Cushman); Dick, L.; Dukes, E.C.; Gabioud, B.; Gaille, F.; Giacomelli, P.; Jeanneret, J.B.; Joseph, C.; Kubischta, W. (Dec 1990). ["Measurement of the inclusive J/ψ production cross sections in and pp collisions at √s = 24.3 GeV"](https://linkinghub.elsevier.com/retrieve/pii/037026939090579U). *Physics Letters B*. **252** (3): 505–510. [doi](/source/Doi_(identifier)):[10.1016/0370-2693(90)90579-U](https://doi.org/10.1016%2F0370-2693%2890%2990579-U).

1. **[^](#cite_ref-6)** Dobinson, Robert W; Pages, J L; Vermeulen, J C (1991). ["Transputers in particle physics experiments"](https://cds.cern.ch/record/233995/files/part.world.2.2.39-45.pdf) (PDF). *Particle World*. **2** (2): 39–45.

1. **[^](#cite_ref-7)** Dukes, Craig (1986). ["PRELIMINARY RESULTS FROM EXPERIMENT UA6 ON INCLUSIVE pi0, eta AND GAMMA PRODUCTION FROM p anti-p COLLISIONS AT S**1/2 = 24-GeV"](https://inspirehep.net/files/05c925c76f56a1a822871122d1fbf24b). *Strong Interactions and Gauge Theories*.

1. **[^](#cite_ref-8)** Camilleri, Leslie (1991). ["Comparison of direct γγ production in pp and pp reactions at √s = 24.3 GeV"](https://cds.cern.ch/record/2119955/files/c90-08-02-p1436.pdf) (PDF). *High-energy physics. Proceedings, 25th International Conference, Singapore, August 2-8, 1990*. Vol. 2. pp. 1436–1438.

1. **[^](#cite_ref-9)** Duclos, Jean (1989-06-19). ["Experiments with internal targets in electron storage rings"](https://dx.doi.org/10.1016/0375-9474%2889%2990456-9). *Nuclear Physics A*. **497**: 77–90. [Bibcode](/source/Bibcode_(identifier)):[1989NuPhA.497...77D](https://ui.adsabs.harvard.edu/abs/1989NuPhA.497...77D). [doi](/source/Doi_(identifier)):[10.1016/0375-9474(89)90456-9](https://doi.org/10.1016%2F0375-9474%2889%2990456-9). [ISSN](/source/ISSN_(identifier)) [0375-9474](https://search.worldcat.org/issn/0375-9474).

1. **[^](#cite_ref-10)** Breedon, R. E.; Chapin, T. J.; Cool, R. L.; Cox, P. T.; Goulianos, K.; Petersen, P. C.; Rusack, R. W.; Snow, G. R.; Vacghi, A.; White, S. N.; Camilleri, L.; Dick, L.; Jeanneret, J. B.; Kubischra, W.; Von Dardel, G. (1989-01-12). ["Precise comparison of antiproton-proton and proton-proton forward elastic scattering at √s = 24.3 GeV"](https://dx.doi.org/10.1016/0370-2693%2889%2991150-7). *Physics Letters B*. **216** (3): 459–465. [Bibcode](/source/Bibcode_(identifier)):[1989PhLB..216..459B](https://ui.adsabs.harvard.edu/abs/1989PhLB..216..459B). [doi](/source/Doi_(identifier)):[10.1016/0370-2693(89)91150-7](https://doi.org/10.1016%2F0370-2693%2889%2991150-7). [ISSN](/source/ISSN_(identifier)) [0370-2693](https://search.worldcat.org/issn/0370-2693).

v t e Super Proton Synchrotron experiments EMU experiments EMU1 EMU2 EMU3 EMU4 EMU5 EMU6 EMU7 EMU8 EMU9 EMU10 EMU11 EMU12 EMU13 EMU14 EMU15 EMU16 EMU17 EMU18 EMU19 EMU20 NA experiments NA1 NA2 NA3 NA4 NA5 NA6 NA7 NA8 NA9 NA10 NA11 NA12/2 NA13 NA14/2 NA15 NA16 NA17 NA18 NA19 NA20 NA21 NA22 NA23 NA24 NA25 NA26 NA27 NA28 NA29 NA30 NA31/2 NA32 NA33 NA34/2/3 NA35 NA36 NA37 NA38 NA39 NA40 NA41 NA42 NA43/2 NA44 NA45/2 NA46 NA47 NA48/1/2 NA49 NA50 NA51 NA52 NA53 NA54 NA55 NA56 NA57 NA58 NA59 NA60 NA61 NA62 NA63 NA64 NA65 NA66 UA experiments UA1 UA2 UA3 UA4/2 UA5/2 UA6 UA7 UA8 UA9 WA experiments WA1/2 WA2 WA3 WA4 WA5 WA6 WA7 WA8 WA9 WA10 WA11 WA12 WA13 WA14 WA15 WA16 WA17 WA18/2 WA19 WA20 WA21 WA22 WA23 WA24 WA25 WA26 WA27 WA28 WA29 WA30 WA31 WA32 WA33 WA34 WA35 WA36 WA37 WA38 WA39 WA40 WA41 WA42 WA43 WA44 WA45 WA46 WA47 WA48 WA49 WA50 WA51 WA52 WA53 WA54 WA55 WA56 WA57 WA58 WA59 WA60 WA61 WA62 WA63 WA64 WA65 WA66 WA67 WA68 WA69 WA70 WA71 WA72 WA73 WA74 WA75 WA76 WA77 WA78 WA79 WA80 WA81 WA82 WA83 WA84 WA85 WA86 WA87 WA88 WA89 WA90 WA91 WA92 WA93 WA94 WA95 WA96 WA97 WA98 WA99/2 WA100 WA101 WA102 WA103

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Adapted from the Wikipedia article [UA6 experiment](https://en.wikipedia.org/wiki/UA6_experiment) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/UA6_experiment?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.