B-meson

B-mesons - mesons consisting of b-antiquark and upper ( $\mathrm {B^{+}}$ ${\ displaystyle \ mathrm {B ^ {+}}}$ ${\ displaystyle \ mathrm {B ^ {+}}}$ ), lower ( $\mathrm {B^{0}}$ ${\ displaystyle \ mathrm {B ^ {0}}}$ ${\ displaystyle \ mathrm {B ^ {0}}}$ ), strange ( $\mathrm {B_{s}^{0}}$ ${\ displaystyle \ mathrm {B_ {s} ^ {0}}}$ ${\ displaystyle \ mathrm {B_ {s} ^ {0}}}$ ) or charmed ( $\mathrm {B_{c}^{+}}$ ${\ displaystyle \ mathrm {B_ {c} ^ {+}}}$ ${\ displaystyle \ mathrm {B_ {c} ^ {+}}}$ ) quark .

The combination of b-antiquark and t-quark ( $\mathrm {t{\bar {b}}}$ ${\ displaystyle \ mathrm {t {\ bar {b}}}}$ ${\ displaystyle \ mathrm {t {\ bar {b}}}}$ ) is considered impossible due to the short lifetime of the latter ^[1] . The combination of b-antiquark and b-quark ( $\mathrm {b{\bar {b}}}$ ${\ displaystyle \ mathrm {b {\ bar {b}}}}$ ${\ mathrm {b {\ bar {b}}}}$ ) is not a B-meson, but a bottomonium .

Each B-meson has antiparticles, which consist of a b-quark and an upper ( $\mathrm {B^{-}}$ ${\ displaystyle \ mathrm {B ^ {-}}}$ ${\ displaystyle \ mathrm {B ^ {-}}}$ ), lower ( $\mathrm {{\bar {B}}^{0}}$ ${\ displaystyle \ mathrm {{\ bar {B}} ^ {0}}}$ ${\ displaystyle \ mathrm {{\ bar {B}} ^ {0}}}$ ), strange ( $\mathrm {{\bar {B}}_{s}^{0}}$ ${\ displaystyle \ mathrm {{\ bar {B}} _ {s} ^ {0}}}$ ${\ displaystyle \ mathrm {{\ bar {B}} _ {s} ^ {0}}}$ ) or charmed ( $\mathrm {B_{c}^{-}}$ ${\ displaystyle \ mathrm {B_ {c} ^ {-}}}$ ${\ displaystyle \ mathrm {B_ {c} ^ {-}}}$ ) antiquarks, respectively.

B-mesons were first discovered in 1983 at the CLEO detector.

Content

Features

B mesons
Particle	Symbol	Anti- particle	Quark composition	Charge	Isospin ( I )	Resting energy (M eV / s ²)	S	C	B '	Lifetime ( c )	Basic decay mode
B-meson	$\mathrm {B^{+}}$ ${\ displaystyle \ mathrm {B ^ {+}}}$	$\mathrm {B^{-}}$ ${\ displaystyle \ mathrm {B ^ {-}}}$	$\mathrm {u{\bar {b}}}$ ${\ displaystyle \ mathrm {u {\ bar {b}}}}$	+1	¹ ⁄ ₂	5279.15 ± 0.31	0	0	+1	(1,638 ± 0,011) ⋅10 ⁻¹²	See B ^± decay modes
Neutral B-meson	$\mathrm {B^{0}}$ ${\ displaystyle \ mathrm {B ^ {0}}}$	$\mathrm {{\bar {B}}^{0}}$ ${\ displaystyle \ mathrm {{\ bar {B}} ^ {0}}}$	$\mathrm {d{\bar {b}}}$ ${\ displaystyle \ mathrm {d {\ bar {b}}}}$	0	¹ ⁄ ₂	5279.53 ± 0.33	0	0	+1	(1,530 ± 0,009) ⋅10 ⁻¹²	See B ⁰ decay modes
Strange B-meson	$\mathrm {B_{s}^{0}}$ ${\ displaystyle \ mathrm {B_ {s} ^ {0}}}$	$\mathrm {{\bar {B}}_{s}^{0}}$ ${\ displaystyle \ mathrm {{\ bar {B}} _ {s} ^ {0}}}$	$\mathrm {s{\bar {b}}}$ ${\ displaystyle \ mathrm {s {\ bar {b}}}}$	0	0	5366.3 ± 0.6	−1	0	+1	(1,470 +0,027 −0.026 ) ⋅10 ⁻¹²	See B 0 s decay fashion
Enchanted B-Maison	$\mathrm {B_{c}^{+}}$ ${\ displaystyle \ mathrm {B_ {c} ^ {+}}}$	$\mathrm {B_{c}^{-}}$ ${\ displaystyle \ mathrm {B_ {c} ^ {-}}}$	$\mathrm {c{\bar {b}}}$ ${\ displaystyle \ mathrm {c {\ bar {b}}}}$	+1	0	6276 ± 4	0	+1	+1	(0.46 ± 0.07) ⋅10 ⁻¹²	See B ± c decay mode

B-meson-antimeson oscillations

Neutral B-mesons, B ⁰ and B 0
s , can spontaneously turn into their antiparticles and vice versa. This phenomenon is called . The existence of neutral B-meson oscillations is one of the main predictions of the Standard Model of elementary particles . She was measured in the system. $\mathrm {B^{0}-{\bar {B}}^{0}}$ ${\ displaystyle \ mathrm {B ^ {0} - {\ bar {B}} ^ {0}}}$ and amounted to about 0.496 p s ⁻¹ ^[2] , and in the system $\mathrm {B_{s}^{0}-{\bar {B}}_{s}^{0}}$ ${\ displaystyle \ mathrm {B_ {s} ^ {0} - {\ bar {B}} _ {s} ^ {0}}}$ - about Δ m _s = 17.77 ± 0.10 _stat. ± 0.07 _syst. ps ⁻¹ . The measurements were carried out in the the Fermi laboratory ^[3] . The first estimate of the lower and upper limits of the oscillation value for the system $\mathrm {B_{s}^{0}-{\bar {B}}_{s}^{0}}$ ${\ displaystyle \ mathrm {B_ {s} ^ {0} - {\ bar {B}} _ {s} ^ {0}}}$ was also carried out by the Fermi laboratory during the ^[4] .

On September 25, 2006, the Fermi laboratory announced the confirmation of the previously theoretically discovered B _s meson oscillations. ^[5] According to a Fermi lab press release:

This first major discovery of Run 2 continues the tradition of Fermi's laboratory discoveries in particle physics, where the lower (1977) and upper (1995) quarks were discovered. Surprisingly, the strange behavior of B_s (pronounced “B Sub S”) - mesons is actually predicted by the Standard Model of elementary particles and forces. The discovery of this oscillatory behavior, thus, once again confirms the accuracy of the Standard Model ...
Previously, at the CDF, physicists measured the rate of matter-antimatter transitions for the B_s meson, consisting of a heavy adorable quark associated with a strange antiquark by a strong nuclear interaction. Currently, they have reached a standard for discoveries in the field of particle physics, in which the probability of erroneous observations should be proved less than 5 to 10 million ( ⁵ ⁄ _{10 000 000} ). For CDF results, this probability is even less, 8 to 100 million ( ⁸ ⁄ _100,000,000 ).

Ronald Kotlak, writing for the Chicago Tribune , called the particle “weird” and stated that the meson “could open the door to a new era of physics” because of its proven interaction with “creepy antimatter” ^[6] .

On May 14, 2010, physicists from the Fermi National Accelerator Laboratory reported that for matter, the oscillations decay 1% more often than for antimatter, which can help explain the superiority of matter over antimatter in the observable Universe ^[7] . However, the results obtained after processing large amounts of data from the LHCb detector did not show any significant deviations from the Standard Model ^[8] .

Notes

↑ A. Quadt. Top quark physics at hadron colliders (neopr.) // European Physical Journal C. - 2006. - T. 48 , No. 3 . - S. 835-1000 . - DOI : 10.1140 / epjc / s2006-02631-6 . - .
↑ http://repository.ubn.ru.nl/bitstream/2066/26242/1/26242.pdf
↑ A. Abulencia ( CDF Collaboration ) et al. Observation of Bs-Bsbar Oscillations (Eng.) // Physical Review Letters : journal. - 2006. - Vol. 97 , no. 24 . - P. 242003 . - DOI : 10.1103 / PhysRevLett . 97.242003 . - . - arXiv : hep-ex / 0609040 .
↑ VM Abazov ( D0 Collaboration ) et al. Direct Limits on the B _s ⁰ Oscillation Frequency // Physical Review Letters : journal. - 2006. - Vol. 97 , no. 2 . - P. 021802 . - DOI : 10.1103 / PhysRevLett . 97.021802 . - . - arXiv : hep-ex / 0603029 .
↑ Fermilab (September 25, 2006). It might be ... It could be ... It is !!! . Press release . Retrieved 2007-12-08 .
↑ R. Kotulak . Antimatter discovery could alter physics: Particle tracked between real world, spooky realm , en: Deseret News (September 26, 2006). Date of treatment December 8, 2007.
↑ A New Clue to Explain Existence
↑ Article on LHCb results

Links

W.-M. Yao et al. (Particle Data Group), J. Phys. G 33, 1 (2006) and 2007 partial update for edition 2008 (URL: http://pdg.lbl.gov)
V. Jamieson. Flipping particle could explain missing antimatter (neopr.) . New Scientist (March 18, 2008). Date of treatment January 23, 2010. Archived on August 6, 2012.

[Quadt-1] A. Quadt. Top quark physics at hadron colliders (neopr.) // European Physical Journal C. - 2006. - T. 48 , No. 3 . - S. 835-1000 . - DOI : 10.1140 / epjc / s2006-02631-6 . - .

[2] ttp://repository.ubn.ru.nl/bitstream/2066/26242/1/26242.pdf

[3] A. Abulencia ( CDF Collaboration ) et al. Observation of Bs-Bsbar Oscillations (Eng.) // Physical Review Letters : journal. - 2006. - Vol. 97 , no. 24 . - P. 242003 . - DOI : 10.1103 / PhysRevLett . 97.242003 . - . - arXiv : hep-ex / 0609040 .

[4] VM Abazov ( D0 Collaboration ) et al. Direct Limits on the B _s ⁰ Oscillation Frequency // Physical Review Letters : journal. - 2006. - Vol. 97 , no. 2 . - P. 021802 . - DOI : 10.1103 / PhysRevLett . 97.021802 . - . - arXiv : hep-ex / 0603029 .

[5] Fermilab (September 25, 2006). It might be ... It could be ... It is !!! . Press release . Retrieved 2007-12-08 .

[6] R. Kotulak . Antimatter discovery could alter physics: Particle tracked between real world, spooky realm , en: Deseret News (September 26, 2006). Date of treatment December 8, 2007.

[7] A New Clue to Explain Existence

[8] Article on LHCb results