Double-charm tetraquark explained

Classification:	meson
Double-charm tetraquark
Composition:	2 charm quarks 1 up antiquark 1 down antiquark
Statistics:	bosonic
Group:	hadron
Electric Charge:	+1
Mass:	^[1]
Spin:	1^+
Isospin:	0^[2]

The double-charm tetraquark (T, cc) is a type of long-lived tetraquark that was discovered in 2021 in the LHCb experiment conducted at the Large Hadron Collider.^{[3] [4] [2] [5]} It contains four quarks: two charm quarks, an anti-up and an anti-down quark.^[1]

It has a theoretical computed mass of .^[1] The discovery showed an exceptionally strong peak, with 20-sigma significance.^[6]

It is hypothesized that studying the behavior of the double-charm tetraquark may play a part in explaining the behavior of the strong force.^[7] Following the discovery of the T, researchers now plan experiments to find its double-beauty counterpart T.^[8] This tetraquark has been found to have a longer lifespan than most known exotic-matter particles.

External links

• Observation and study of the doubly charmed T_cc⁺ tetraquark at LHCb: presentation by Ivan Polyaokov at CERN, 2021-09-14

Notes and References

1. Agaev . S.S. . Azizi . K. . Sundu . H. . Newly observed exotic doubly charmed meson T ^{+} _{cc} . Nuclear Physics B . February 2022 . 975 . 115650 . 10.1016/j.nuclphysb.2022.115650. 2108.00188. 236772263 .
2. Aaij . R. . Abdelmotteleb . A. S. W. . Abellán Beteta . C. . Abudinen Gallego . F. J. . Ackernley . T. . Adeva . B. . Adinolfi . M. . Afsharnia . H. . Agapopoulou . C. . Aidala . C. A. . Aiola . S. . 2022-06-16 . Observation of an exotic narrow doubly charmed tetraquark . Nature Physics . 18 . 7 . en . 751–754 . 10.1038/s41567-022-01614-y . 2109.01038 . 2022NatPh..18..751L . 237385202 . 1745-2481.
3. Web site: What to Know About the Newly Discovered Tetraquark at the Large Hadron Collider. 2021-09-27. Gizmodo. 2 August 2021 . en-us.
4. Web site: Twice the charm: long-lived exotic particle discovered. 2021-09-29. CERN. en.
5. Aaij . R. . Abdelmotteleb . A. S. W. . Beteta . C. Abellán . Gallego . F. J. Abudinen . Ackernley . T. . Adeva . B. . Adinolfi . M. . Afsharnia . H. . Agapopoulou . C. . Aidala . C. A. . Aiola . S. . 2022-06-16 . Study of the doubly charmed tetraquark T⁺_cc . Nature Communications . en . 13 . 1 . 3351 . 10.1038/s41467-022-30206-w . 35710739 . 9203551 . 2041-1723.
6. Web site: LHCb experiment spots extraordinary double charmed tetraquark. 2021-09-27. Nikhef. en-US.
7. Web site: Wood. Charlie. 2021-09-27. 'Impossible' Particle Discovery Adds Key Piece to the Strong Force Puzzle. 2021-09-27. Quanta Magazine. en.
8. Web site: Turner. Ben. 2021-08-05. New 'doubly charming' particle could help unlock the secrets of how matter is built. 2021-09-27. livescience.com. en.