Pomeron#Odderon

While other trajectories lead to falling cross sections, the pomeron can lead to logarithmically rising cross sections — which, experimentally, are approximately constant ones.{{Citation needed|date=December 2024}} The identification of the pomeron and the prediction of its properties was a major success of the Regge theory of strong interaction phenomenology. In later years, a BFKL pomeron was derived in further kinematic regimes from perturbative calculations in QCD, but its relationship to the pomeron seen in soft high energy scattering is still not fully understood.{{Citation needed|date=December 2024}}

One consequence of the pomeron hypothesis is that the cross sections of proton–proton and proton–antiproton scattering should be equal at high enough energies. This was demonstrated by the Soviet physicist Isaak Pomeranchuk by analytic continuation assuming only that the cross sections do not fall.{{Citation needed|date=December 2024}} The pomeron itself was introduced by Vladimir Gribov, and it incorporated this theorem into Regge theory.{{Citation needed|date=December 2024}} Geoffrey Chew and Steven Frautschi introduced the pomeron in the West. {{Citation needed|date=December 2024}} The modern interpretation of Pomeranchuk's theorem is that the pomeron has no conserved charges—the particles on this trajectory have the quantum numbers of the vacuum.{{Citation needed|date=December 2024}}

The pomeron was well accepted in the 1960s despite the fact that the measured cross sections of proton–proton and proton–antiproton scattering at the energies then available were unequal.{{Citation needed|date=December 2024}}

The pomeron carries no charges. The absence of electric charge implies that pomeron exchange does not lead to the usual shower of Cherenkov radiation, while the absence of color charge implies that such events do not radiate pions.{{Citation needed|date=December 2024}}

This is in accord with experimental observation. In high energy proton–proton and proton–antiproton collisions in which it is believed that pomerons have been exchanged, a rapidity gap is often observed: This is a large angular region in which no outgoing particles are detected.{{Citation needed|date=December 2024}}

{{main article|Odderon}}

The odderon, the counterpart of the pomeron that carries odd charge parity, was introduced in 1973 by Leszek Łukaszuk and Basarab Nicolescu.{{cite journal | journal = Lettere al Nuovo Cimento | volume = 8 | issue = 7 | year = 1973 | pages = 405–413 | first1 = Leszek | last1 = Łukaszuk | first2 = Basarab | last2 = Nicolescu | title = A possible interpretation of pp rising total cross-sections | doi=10.1007/bf02824484| s2cid = 122981407 }} Odderons exist in QCD as a compound state of three reggeized gluons.{{Cite journal|last1=Martynov|first1=Evgenij|last2=Nicolescu|first2=Basarab|date=March 2018|title=Did TOTEM experiment discover the Odderon?|journal=Physics Letters B|volume=778|pages=414–418|doi=10.1016/j.physletb.2018.01.054|doi-access=free|bibcode=2018PhLB..778..414M|arxiv=1711.03288|s2cid=56064476}} Potentially theorized in 2015.{{Cite web |last1=Ster |first1=András |last2=Csörgő |first2=T. |last3=Jenkovszky |first3=L. |title=Extracting the Odderon from pp and pp scattering data |url=https://indico.cern.ch/event/464154/contributions/1137913/attachments/1204865/1755264/zimanyi_ster_2015_2_odd.pdf |access-date=3 November 2023 |website=indico.cern.ch}} It was potentially observed only in 2017 by the TOTEM experiment at the LHC. This observation was later confirmed in a joint analysis with the DØ experiment at the Tevatron and appeared in the media as the particle's discovery in March 2021.{{cite journal |title=Odderon discovered |editor=Matthew Chalmers | date=9 March 2021 | url=https://cerncourier.com/a/odderon-discovered/ |journal=CERN Courier |access-date=18 March 2021}}{{cite journal |arxiv=2012.03981|last1=Abazov|first1=V. M.|last2=Abbott|first2=B.|last3=Acharya|first3=B. S.|last4=Adams|first4=M.|last5=Adams|first5=T.|last6=Agnew|first6=J. P.|last7=Alexeev|first7=G. D.|last8=Alkhazov|first8=G.|last9=Alton|first9=A.|last10=Antchev|first10=G.|last11=Askew|first11=A.|last12=Aspell|first12=P.|last13=Atanassov|first13=I.|last14=Atkins|first14=S.|last15=Augsten|first15=K.|last16=Aushev|first16=V.|last17=Aushev|first17=Y.|last18=Avati|first18=V.|last19=Avila|first19=C.|last20=Badaud|first20=F.|last21=Baechler|first21=J.|last22=Bagby|first22=L.|last23=Baldenegro Barrera|first23=C.|last24=Baldin|first24=B.|last25=Bandurin|first25=D. V.|last26=Banerjee|first26=S.|last27=Barberis|first27=E.|last28=Baringer|first28=P.|last29=Bartlett|first29=J. F.|last30=Bassler|first30=U.|title=Odderon Exchange from Elastic Scattering Differences between pp and pp¯ Data at 1.96 TeV and from pp Forward Scattering Measurements|journal=Physical Review Letters|year=2021|volume=127|issue=6|page=062003|doi=10.1103/PhysRevLett.127.062003|pmid=34420329|bibcode=2021PhRvL.127f2003A|s2cid=227737845|display-authors=1}}{{cite news |last=Pastore |first=Rose |title=Physicists Discover the Elusive Odderon, First Predicted 50 Years Ago |url=https://gizmodo.com/physicists-discover-the-elusive-odderon-first-predicte-1846513075 |date=19 March 2021 |work=Gizmodo |access-date=19 March 2021 }}{{Cite journal|doi = 10.1140/epjc/s10052-021-08867-6| arxiv=1912.11968 |doi-access=free |title = Evidence of Odderon-exchange from scaling properties of elastic scattering at TeV energies|year = 2021|last1 = Csörgő|first1 = T.|last2 = Novák|first2 = T.|last3 = Pasechnik|first3 = R.|last4 = Ster|first4 = A.|last5 = Szanyi|first5 = I.|journal = The European Physical Journal C|volume = 81|issue = 2|page = 180|bibcode = 2021EPJC...81..180C|s2cid = 209500465}}{{cite web |url=https://www.lunduniversity.lu.se/article/researchers-find-evidence-elusive-odderon-particle|title=Researchers find evidence of elusive Odderon particle|date=18 March 2021|publisher=Lund University}}{{Cite journal|doi=10.1051/epjconf/202023506002|doi-access=free|title=Proton Holography Discovering Odderon from Scaling Properties of Elastic Scattering|year=2020|last1=Csörgö|first1=T.|last2=Novák|first2=T.|last3=Pasechnik|first3=R.|last4=Ster|first4=A.|last5=Szanyi|first5=I.|journal=EPJ Web of Conferences|volume=235|page=06002|arxiv=2004.07095|bibcode=2020EPJWC.23506002C|s2cid=215768713}}{{Excessive citations inline|reason=Six is too many, please group them|date=December 2024}}

In early particle physics, the 'pomeron sector' was what is now called the 'closed string sector' while what was called the 'reggeon sector' is now the 'open string theory'.{{Citation needed|date=December 2024}}

• Giuseppe Cocconi
• Tamás Csörgő

{{Reflist}}

• {{cite book | vauthors = Forshaw JR, Ross DA | year = 2022 | title = Quantum Chromodynamics and the Pomeron | publisher = Cambridge University Press | url = https://www.cambridge.org/core/books/quantum-chromodynamics-and-the-pomeron/778AB1255064D6D8211EA04F353D99E3 | isbn = 9781009290111}}
• {{Cite book

|year=2003

|chapter=Pomeron Physics and QCD

|arxiv=hep-ph/0312279

|author1=Nachtmann, Otto

|doi=10.1142/9789812702722_0023

|title=New Trends in Hera Physics

|pages=253–267

|bibcode=2004nthp.conf..253N

|isbn=978-981-238-835-3

|s2cid=18657919

}}

• [http://www-cdf.fnal.gov/PES/sdd.html Pomerons at Fermilab]
• {{Cite web|title=The odd(eron) couple|url=https://www.symmetrymagazine.org/article/the-odderon-couple|website=symmetry magazine|date=6 July 2021 |language=en}}

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Category:Subatomic particles

Category:Quantum chromodynamics

Category:Hadrons

Category:Hypothetical particles