List of baryons

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This is a list of known and predicted baryons. Baryons are made of quarks and as such are part of the subatomic particle family called the hadrons. Baryons are the sub-family of hadrons with a baryon number of 1, as opposed to the mesons which are the sub-family of hadrons with a baryon number of 0. Since baryons are composed of quarks they participate in the strong interaction. Leptons are not composed of quarks and as such do not participate in the strong interaction. Protons and neutrons that make up most of the visible matter in the universe are both baryons, whereas electrons (the other major component of atoms) is a lepton.

Traditionally, baryons were believed to be composed of only three quarks (triquarks) (quarks have a baryon number of 1⁄3 and anti-quarks have a baryon number of −1⁄3). Recently, physicists have reported the existence of pentaquarks—"exotic" baryons made of four quarks and one antiquark, but their existence is not generally accepted.[1][2] Each baryon has a corresponding antiparticle (antibaryon) where quarks are replaced by their corresponding antiquarks and vice versa. For example, a proton is made of two up quarks and one down quark; thus, the antiproton is made of two up antiquarks and one down antiquark.

Contents

[edit] Overview

[edit] Spin, orbital angular momentum , and total angular momentum

Main articles: Spin (physics), Orbital angular momentum, Total angular momentum, and Quantum numbers

Spin (quantum number S) is a vector quantity that represents the "intrinsic" angular momentum of a particle. It comes in increments of 1⁄2 ℏ (pronounced "h-bar"). The ℏ is often dropped because it is the "fundamental" unit of spin, and it is implied that "spin 1" means "spin 1 ℏ". In some systems of natural units, ℏ is chosen to be 1, therefore does not appear anywhere.

Quarks are fermionic particles of spin 1⁄2 (S = 1⁄2). Because spin projections varies in increments of 1 (that is 1 ℏ), a single quark has a spin vector of length 1⁄2, and has two spin projections (Sz = +1⁄2 and Sz = −1⁄2). Two quarks can have their spins aligned, in which case the two spin vectors add to make a vector of length S = 1 and three spin projections (Sz = +1, Sz = 0, and Sz = −1). If two quarks have unaligned spins, the spin vectors add up to make a vector of length S = 0 and has only one spin projection (Sz = 0), etc. Since baryons are made of three quarks, their spin vectors can add to make a vector of length S = 3⁄2 which has four spin projections (Sz = +3⁄2, Sz = +1⁄2, Sz = −1⁄2, and Sz = −3⁄2), or a vector of length S = 1⁄2 with two spin projections (Sz = +1⁄2, and Sz = −1⁄2).[3]

There is another quantity of angular momentum, called the orbital angular momentum (quantum number L), that also comes in increments of 1⁄2 ℏ, which represent the angular moment of due to particles orbiting around each other. The total angular momentum (quantum number J) of a particle is therefore the combination of intrinsic angular momentum (spin) and orbital angular momentum (J = S + L).[3]

Particles physicists are most interested in baryons with no orbital angular momentum (L = 0), therefore the two groups of baryons most studied are the S = 1⁄2; L = 0 and S = 3⁄2; L = 0, which corresponds to J = 1⁄2 and J = 3⁄2, although they are not the only ones. It is also possible to obtain J = 3⁄2 particles from S = 1⁄2 and L = 1. How to distinguish between the S = 3⁄2, L = 0 and S = 1⁄2, L = 1 baryons is an active area of research in baryon spectroscopy[4][5].

[edit] Parity

Main articles: Parity (physics), Wavefunction, and Even and odd functions

Parity refers to whether the wavefunction of a particle is even or odd. A positive parity (P = +) means that the wavefunction is even, while a negative (P = −) means the wavefunction is odd.[3]

|\Psi(x)\rangle = x^3e^{-x^2} is an odd 1-dimensional wavefunction because |\Psi(x)\rangle=-|\Psi(-x)\rangle
|\Psi(x)\rangle = x^4e^{-x^2} is an even 1-dimensional wavefunction because |\Psi(x)\rangle=|\Psi(-x)\rangle

For baryons, the parity is related to the orbital angular momentum by the relation:[6]

P = ( − 1)L.

Physicists are often particularly interested in baryons with no orbital angular momentum (L = 0), which are of even parity (P = +).

[edit] Isospin and charge

Combinations of three u, d or s quarks forming baryons with a spin–3⁄2 form the uds baryon decuplet.
Combinations of three u, d or s quarks forming baryons with a spin–3⁄2 form the uds baryon decuplet.
Combinations of three u, d or s quarks forming baryons with a spin–1⁄2 form the uds baryon octet
Combinations of three u, d or s quarks forming baryons with a spin–1⁄2 form the uds baryon octet
Main article: Isospin

Observation of baryons prior to the development of the quark model led particle physicists to believe that some particles were so similar in how they interact with the strong nuclear force, and so similar in mass, that they were really the same particle even though they had different charge. This was due to the fact that prior to the development of the quark model, only baryons made of u, d and s quarks were known (although this wasn't known at the time). Since the mass of the u and d quarks are very similar, particles made of the same number of u and d quarks have the same mass, and the exact u and d quark composition specifies the charge (u carries charge +2⁄3 while d carries charge −1⁄3. For example the four Deltas have different charges (Δ++ (uuu), Δ+ (uud), Δ0 (udd), Δ− (ddd)), but the same mass (~1,232 MeV/c2), and was considered to be a single particle in different charged states.

To explain the different charges, particles physicist came up with the concept of isospin, whose projections varied in increments of 1 just like spin, where the charges corresponded to different isospin projections. Since the "Delta particle" had four "charged states" of mass 1,232 MeV/c2, the delta was said to be of isospin I = 3⁄2 whose four charged state Δ++, Δ+, Δ0, and Δ− corresponded to Iz = +3⁄2, Iz = +1⁄2, Iz = −1⁄2, and Iz = −3⁄2 respectively. Another example is the two nucleons (the proton (uud) and neutron (udd)). The positive nucleon N+ (proton) and the neutral nucleon N0 (neutron)—each of mass ~938 MeV/c2—were given isospin I = 1⁄2, and the projections Iz = +1⁄2 and Iz = −1⁄2 respectively.[7]

In the "isospin picture", the four Deltas and the two nucleons were thought to be the different states of two particles. However in the quark model, Deltas are different states of nucleons (the N++ or N− are forbidden by Pauli's exclusion principle). Isospin, although conveying an inaccurate picture of things, is still used to classify baryons, leading to unnatural and often confusing nomenclature. It was noted that the isospin projections were related to the up and down quark content of particles by the relation:

I_z=\frac{1}{2}[(n_u-n_\bar{u})-(n_d-n_\bar{d})]

where the n's are the number of up and down quarks and anti-quarks.

[edit] Flavour quantum numbers

Main article: Flavour (particle physics)#Flavour quantum numbers

The strangeness flavour quantum number S (not to be confused with spin) was noticed to go up and down along with particle mass. The higher the mass, the lower the strangeness (the more s quarks). Particles could be described with isospin projections (related to charge) and strangeness (mass) (see the uds octet and decuplet figures on the right). As other quarks where discovered, new quantum numbers were made to have similar description of udc and udb octets and decuplets. Since only the u and d mass are similar, this description of particle mass and charge in terms of isospin and flavour quantum numbers only works well for octet and decuplet made of one u, one d and one other quark and breaks down for the other octets and decuplets (for example ucb octet and decuplet). If the quarks all had the same mass, their behaviour would be called symmetric, as they would all behave in exactly the same way with respect to the strong interaction. Since quarks do not have the same mass, they do not interact in the same way (exactly like an electron placed in an electric field will accelerate more than a proton placed in the same field because of its lighter mass), and the symmetry is said to be broken.

It was noted that charge (Q) was related to the isospin projection (Iz), the baryon number (B) and flavour quantum numbers (S, C, B′, T) by the Gell-Mann–Nishijima formula:[7]

Q=I_z+\frac{1}{2}(B+S+C+B^\prime+T)

S, C, B′, and T represent the strangeness, charmness, bottomness and topness flavour quantum numbers respectively. They are related to the number of strange, charm, bottom, and top quarks and antiquark according to the relations:

S=-(n_s-n_\bar{s})
C=+(n_c-n_\bar{c})
B^\prime=-(n_b-n_\bar{b})
T=+(n_t-n_\bar{t})

meaning that the Gell-Man–Nishijima formula is equivalent to the expression of charge in terms of quark content:

Q=\frac{2}{3}[(n_u-n_\bar{u})+(n_c-n_\bar{c})+(n_t+n_\bar{t})]-\frac{1}{3}[(n_d-n_\bar{d})+(n_s-n_\bar{s})+(n_b+n_\bar{b})]

[edit] Particle classification

Baryons are classified into groups according to their isospin (I) values and quark (q) content. There are six groups of triquarks—nucleon (N), Delta (Δ), Lambda (Λ), Sigma (Σ), Xi (Ξ), and Omega (Ω). The rules for classification are defined by the Particle Data Group. These rules consider the up (u), down (d) and strange (s) quarks to be light and the charm (c), bottom (b), and top (t) to be heavy. The rules cover all the particles that can be made from three of each of the six quarks, even though baryons made of t quarks are not expected to exist because of the t quark's short lifetime. The rules do not cover pentaquarks.[8]

  • Baryons with three u and/or d quarks are N's (I = 1⁄2) or Δ's (I = 3⁄2).
  • Baryons with two u and/or d quarks are Λ's (I = 0) or Σ's (I = 1). If the third quark is heavy, its identity is given by a subscript.
  • Baryons with one u or d quark are Ξ's (I = 1⁄2). One or two subscripts are used if one or both of the remaining quarks are heavy.
  • Baryons with no u or d quarks are Ω's (I = 0), and subscripts indicate any heavy quark content.
  • Baryons that decay strongly have their masses as part of their names. For example, Σ0 does not decay strongly, but Δ++(1232) does.

It is also a widespread (but not universal) practice to follow some additional rules when distinguishing between some states which would otherwise have the same symbol.[7]

  • Baryons in total angular momentum J = 3⁄2 configuration which have the same symbols as their J = 1⁄2 counterparts are denoted by an asterisk ( * ).
  • Two baryons can be made of three different quarks in J = 1⁄2 configuration. In this case, a prime ( ′ ) is used to distinguish between them.
  • Exception: When two of the three quarks are one up and one down quark, one baryon is dubbed Λ while the other is dubbed Σ.

Quarks carry charge, so knowing the charge of a particle indirectly gives the quark content. For example, the rules above say that a Ξ+c contains a c quark and some combination of two u and/or d quarks. The c quark as a charge of (Q = +2⁄3), therefore the other two must be a u quark (Q = +2⁄3), and a d quark (Q = −1⁄3) to have the correct total charge (Q = 1).

[edit] Lists of baryons

These lists detail all known and predicted triquark baryons in total angular momentum J = 1⁄2 and J = 3⁄2 configurations with positive parity, as well as all the reported pentaquark baryons.

The symbols encountered in these lists are: I (isospin), J (total angular momentum), P (parity), u (up quark), d (down quark), s (strange quark), c (charm quark), b (bottom), Q (charge), B (baryon number), S (strangeness), C (charmness), B′ (bottomness), as well as a wide array of subatomic particles (hover for name).

Antiparticles are not listed in the tables; however, they simply would have all quarks changed to antiquarks (and antiquarks changed to quarks), and Q, B, S, C, B′, would be of opposite signs. Particles with † next to their names have been predicted by the standard model but not yet observed. I, J, and P values marked with *'s have not been firmly established by experiments, but are predicted by the quark model and are consistent with the measurements.[9][10]

[edit] JP = 1⁄2+ baryons (triquarks)

JP = 1⁄2+ baryons (triquarks)
Particle name Symbol Quark
content		 Rest mass (MeV/c2) I JP Q (e) S C B' Mean lifetime (s) Commonly decays to
Nucleon/proton [11] p / p+ / N+ uud 0,938.272 029 ± 0.000 080[a] 1⁄2 1⁄2+ +1 0 0 0 Stable[b] Unobserved
Nucleon/neutron [12] n / n0 / N0 udd 0,939.565 360 ± 0.000 081[a] 1⁄2 1⁄2+ 0 0 0 0 885.7 ± 0.8[c] p+ + e− + νe
Lambda [13] Λ0 uds 1,115.683 ± 0.006 0 1⁄2+ 0 −1 0 0 2.631 ± 0.020 × 10-10 p+ + π− or
n0 + π0
charmed Lambda [14] Λ+c udc 2,286.46 ± 0.14 0 1⁄2* + +1 0 +1 0 2.00 ± 0.06 × 10-13 See Λ+c decay modes
bottom Lambda [15] Λ0b udb 5,620.2 ± 1.6 0* 1⁄2* +* 0 0 0 −1 1.409+0.055-0.054 × 10-12 See Λ0b decay modes
Sigma [16] Σ+ uus 1,189.37 ± 0.07 1 1⁄2+ +1 −1 0 0 8.018 ± 0.026 × 10-11 p+ + π0 or

n0 + π+
Sigma [17] Σ0 uds 1,192.642 ± 0.024 1 1⁄2+ 0 −1 0 0 7.4 ± 0.7 × 10-20 Λ0 + γ
Sigma [18] Σ− dds 1,197.449 ± 0.030 1 1⁄2+ −1 −1 0 0 1.479 ± 0.011 × 10-10 n0 + π−
charmed Sigma [19] Σ++c(2455) uuc 2,454.02 ± 0.18 1 1⁄2* +* +2 0 +1 0 Unknown Λ+c + π+
charmed Sigma [19] Σ+c(2455) udc 2,452.9 ± 0.4 1 1⁄2* +* +1 0 +1 0 Unknown Λ+c + π0
charmed Sigma [19] Σ0c(2455) ddc 2,453.76 ± 0.18 1 1⁄2* +* 0 0 +1 0 Unknown Λ+c + π−
bottom Sigma [20] Σ+b(?[d]) uub 5,807.8+3.7-3.9 1* 1⁄2* +* +1 0 0 −1 Unknown Λ0b + π+ (seen)
bottom Sigma† Σ0b(?[d]) udb Unknown 1* 1⁄2* +* 0 0 0 −1 Unknown Unknown
bottom Sigma [20] Σ−b(?[d]) ddb 5,815.2 ± 2.7 1* 1⁄2* +* −1 0 0 −1 Unknown Λ0b + π− (seen)
Xi [21] Ξ0 uss 1,314.86 ± 0.20 1⁄2 1⁄2+* 0 −2 0 0 2.90 ± 0.09 × 10-10 Λ0 + π0
Xi [22] Ξ− dss 1,321.71 ± 0.07 1⁄2 1⁄2+* −1 −2 0 0 1.639 ± 0.015 × 10-10 Λ0 + π−
charmed Xi[23] Ξ+c usc 2,467.9 ± 0.4 1⁄2 1⁄2* +* +1 −1 +1 0 4.42 ± 0.26 × 10-13 See Ξ+c decay modes
charmed Xi[23] Ξ0c dsc 2,471.0 ± 0.4 1⁄2 1⁄2* +* 0 −1 +1 0 1.12+0.13 × 10-13 See Ξ0c decay modes
charmed Xi prime[23] Ξ′+c usc 2,575.7 ± 3.1 1⁄2 1⁄2* +* +1 −1 +1 0 Unknown Ξ+c+γ (seen)
charmed Xi prime[23] Ξ′0c dsc 2,578.0 ± 2.9 1⁄2 1⁄2* +* +1 −1 +1 0 Unknown Ξ0c+γ (seen)
double charmed Xi[e]† Ξ++cc ucc Unknown 1⁄2* 1⁄2* +* +2 0 +2 0 Unknown Unknown
double charmed Xi[e] [24] Ξ+cc dcc 3,518.9 ± 0.9[c] 1⁄2* 1⁄2* +* +1 0 +2 0 <3.3 × 10-14[e] Λ+c + K− + π+[e] or
p+ + D+ + K−[e]
bottom Xi (or Cascade B) [25] Ξ0b usb Unknown 1⁄2* 1⁄2* +* 0 −1 0 −1 1.42+0.28-0.24 × 10-12[f] See Ξb decay modes
bottom Xi (or Cascade B) [25][26][27] Ξ−b dsb 5,792.9 ± 4.2 1⁄2* 1⁄2* +* −1 −1 0 −1 1.42+0.28-0.24 × 10-12[f] See Ξb decay modes
(Ξ− + J/ψ was also seen)
bottom Xi prime† Ξ′0b usb Unknown 0* 1⁄2* +* 0 −1 0 −1 Unknown Unknown
bottom Xi prime† Ξ′−b dsb Unknown 0* 1⁄2* +* 0 −1 0 −1 Unknown Unknown
double bottom Xi† Ξ0bb ubb Unknown 1⁄2* 1⁄2* +* 0 0 0 −2 Unknown Unknown
double bottom Xi† Ξ−bb dbb Unknown 1⁄2* 1⁄2* +* −1 0 0 −2 Unknown Unknown
charmed bottom Xi† Ξ+cb ucb Unknown 1⁄2* 1⁄2* + +1 0 +1 −1 Unknown Unknown
charmed bottom Xi† Ξ0cb dcb Unknown 1⁄2* 1⁄2* +* 0 0 +1 −1 Unknown Unknown
charmed bottom Xi prime† Ξ′+cb ucb Unknown 0* 1⁄2* + +1 0 +1 −1 Unknown Unknown
charmed bottom Xi prime† Ξ′0cb dcb Unknown 0* 1⁄2* + +1 0 +1 −1 Unknown Unknown
charmed Omega[28] Ω0c ssc 2,697.5 ± 2.6 0 1⁄2* +* 0 −2 +1 0 6.9 ± 1.2 × 10-14 See Ω0c decay modes
bottom Omega† Ω−b ssb Unknown 0* 1⁄2* +* −1 −2 0 −1 Unknown Unknown
double charmed Omega† Ω+cc scc Unknown 0* 1⁄2* +* +1 −1 +2 0 Unknown Unknown
charmed bottom Omega† Ω0cb scb Unknown 0* 1⁄2* +* 0 −1 +1 −1 Unknown Unknown
charmed bottom Omega prime† Ω′0cb scb Unknown 0* 1⁄2* +* 0 −1 +1 −1 Unknown Unknown
double bottom Omega† Ω−bb sbb Unknown 0* 1⁄2* +* −1 −1 0 −2 Unknown Unknown
double charmed bottom Omega† Ω+ccb ccb Unknown 0* 1⁄2* +* +1 0 +2 −1 Unknown Unknown
charmed double bottom Omega† Ω0cbb cbb Unknown 0* 1⁄2* +* 0 0 +1 −2 Unknown Unknown

[a] The masses of the proton and neutron are known with much better precision in atomic mass units than in Electron volt/c², due to the relatively poorly known value of the elementary charge. In atomic mass unit, the mass of the proton is 1.007 276 466 88(13) u while that of the neutron is 1.008 664 915 60(55) u.
[b] At least 1035 years. See proton decay.
[c] For free neutrons; in most common nuclei, neutrons are stable.
[d] The specific values of the name hasn't been decided yet. Will probably end up to something close to Σb(5810)
[e] Some controversy exists about this data. See references
[f] This is actually a measurement of the average lifetime of b-baryons that decay to a jet containing a same sign Ξ∓l∓ pair. Presumably the mix is mainly Ξb, with some Λb.

[edit] JP = 3⁄2+ baryons (triquarks)

JP = 3⁄2+ baryons (triquarks)
Particle name Symbol Quark
content		 Rest mass (MeV/c²) I JP Q (e) S C B' Mean lifetime (s) Commonly decays to
Delta [29] Δ++(1232) uuu 1,232 ± 1 3⁄2 3⁄2+ +2 0 0 0 6 × 10-24 [30] p+ + π+
Delta [29] Δ+(1232) uud 1,232 ± 1 3⁄2 3⁄2+ +1 0 0 0 6 × 10-24 [30] π+ + n0 or

π0 + p+
Delta [29] Δ0(1232) udd 1,232 ± 1 3⁄2 3⁄2+ 0 0 0 0 6 × 10-24 [30] π0 + n0 or

π− + p+
Delta [29] Δ−(1232) ddd 1,232 ± 1 3⁄2 3⁄2+ −1 0 0 0 6 × 10-24 [30] π− + n0
Sigma [31] Σ∗+(1385) uus 1,382.8 ± 0.4 1 3⁄2+ +1 −1 0 0 Unknown Λ0 + π+ or

Σ+ + π0 or
Σ0 + π+
Sigma [31] Σ∗0(1385) uds 1,383.7 ± 1.0 1 3⁄2+ 0 −1 0 0 Unknown Λ0 + π0 or

Σ+ + π− or
Σ0 + π0
Sigma [31] Σ∗-(1385) dds 1,387.2 ± 0.5 1 3⁄2+ −1 −1 0 0 Unknown Λ0 + π− or

Σ0 + π− or
Σ− + π0 or
charmed Sigma [32] Σ∗++c(2520) uuc 2,518.4 ± 0.6 1 3⁄2* +* +2 0 +1 0 Unknown Λ+c + π+
charmed Sigma [32] Σ∗+c(2520) udc 2,517.5 ± 2.3 1 3⁄2* +* +1 0 +1 0 Unknown Λ+c + π0
charmed Sigma [32] Σ∗0c(2520) ddc 2,518.0 ± 0.5 1 3⁄2* +* 0 0 +1 0 Unknown Λ+c + π−
bottom Sigma† Σ∗+b uub Unknown 1* 3⁄2* +* +1 0 0 −1 Unknown Unknown
bottom Sigma† Σ∗0b udb Unknown 1* 3⁄2* +* 0 0 0 −1 Unknown Unknown
bottom Sigma† Σ∗−b ddb Unknown 1* 3⁄2* +* −1 0 0 −1 Unknown Unknown
Xi [33] Ξ∗0(1530) uss 1,531.80 ± 0.32 1⁄2 3⁄2+ 0 −2 0 0 Unknown Ξ0 + π0 or

Ξ− + π+
Xi [33] Ξ∗−(1530) dss 1,535.0 ± 0.6 1⁄2 3⁄2+ −1 −2 0 0 Unknown Ξ0 + π− or

Ξ− + π0
charmed Xi [34] Ξ∗+c(2645) usc 2,646.6 ± 1.4 1⁄2 3⁄2* +* +1 −1 +1 0 Unknown Ξ+c + π0 (seen)
charmed Xi [34] Ξ∗0c(2645) dsc 2,646.1 ± 1.2 1⁄2 3⁄2* +* 0 −1 +1 0 Unknown Ξ+c + π− (seen)
double charmed Xi† Ξ∗++cc ucc Unknown 1⁄2* 3⁄2* +* +2 0 +2 0 Unknown Unknown
double charmed Xi† Ξ∗+cc dcc Unknown 1⁄2* 3⁄2* +* +1 0 +2 0 Unknown Unknown
bottom Xi† Ξ∗0b usb Unknown 1⁄2* 3⁄2* +* 0 −1 0 −1 Unknown Unknown
bottom Xi† Ξ∗−b dsb Unknown 1⁄2* 3⁄2* +* −1 −1 0 −1 Unknown Unknown
double bottom Xi† Ξ∗0bb ubb Unknown 1⁄2* 3⁄2* +* 0 0 0 −2 Unknown Unknown
double bottom Xi† Ξ∗−bb dbb Unknown 1⁄2* 3⁄2* +* −1 0 0 −2 Unknown Unknown
charmed bottom Xi† Ξ∗+cb ucb Unknown 1⁄2* 3⁄2* +* +1 0 +1 −1 Unknown Unknown
charmed bottom Xi† Ξ∗0cb dcb Unknown 1⁄2* 3⁄2* +* 0 0 +1 −1 Unknown Unknown
Omega [35] Ω− sss 1,672.45 ± 0.29 0 3⁄2+ −1 −3 0 0 8.21 ± 0.11 × 10-11 Λ0 + K− or
Ξ0 + π− or

Ξ− + π0
charmed Omega [36] Ω∗0c(2770) ssc 2,768.3 ± 1.5 0 3⁄2* +* 0 −2 +1 0 Unknown Ω0c+γ
bottom Omega† Ω∗−b ssb Unknown 0* 3⁄2* +* −1 −2 0 −1 Unknown Unknown
double charmed Omega† Ω∗+cc scc Unknown 0* 3⁄2* +* +1 −1 +2 0 Unknown Unknown
charmed bottom Omega† Ω∗0cb scb Unknown 0* 3⁄2* +* 0 −1 +1 −1 Unknown Unknown
double bottom Omega† Ω∗−bb sbb Unknown 0* 3⁄2* +* −1 −1 0 −2 Unknown Unknown
triple charmed Omega† Ω++ccc ccc Unknown 0* 3⁄2* +* +2 0 +3 0 Unknown Unknown
double charmed bottom Omega† Ω∗+ccb ccb Unknown 0* 3⁄2* +* +1 0 +2 −1 Unknown Unknown
charmed double bottom Omega† Ω∗0cbb cbb Unknown 0* 3⁄2* +* 0 0 +1 −2 Unknown Unknown
triple bottom Omega† Ω−bbb bbb Unknown 0 3⁄2* +* −1 0 0 −3 Unknown Unknown

[edit] Exotic baryons (pentaquarks)

This lists details pentaquarks reported to exist. However, other groups have looked for them and reported to have found nothing. Data is controversial to the point that the existence of pentaquarks is not generally accepted.

Exotic baryons (pentaquarks)
Particle name Symbol Quark
content		 Rest mass (MeV/c²) I JP Q (e) S C B' Mean lifetime (s) Commonly decays to
Theta [37] Θ+ (1540) uudds 1,533.6 ± 2.4 0 Unknown +1 +1 0 0 Unknown K0 + p+ or
K+ + n0
Charmed Theta [38] Θ0c (3100) uuddc 3,099 ± 8 0 Unknown 0 0 −1 0 Unknown Unknown
Phi [39] Φ0 (1860) ssddu 1,862 ± 2 3⁄2 Unknown 0 −2 0 0 Unknown Unknown

[edit] See also

[edit] References

  1. ^ Muir (2003)
  2. ^ Carter (2003)
  3. ^ a b c Shankar (1994)
  4. ^ Garcilazo et. al. (2007)
  5. ^ Manley (2009)
  6. ^ Wong (1998a)
  7. ^ a b c Wong (1998b)
  8. ^ Yao et al. (2006): Naming scheme for hadrons
  9. ^ Yao et al. (2006): Particle summary tables - Baryon
  10. ^ Körner et al. (1994)
  11. ^ Yao et al. (2006): Particle listings—Proton
  12. ^ Yao et al. (2006): Particle listings—Neutron
  13. ^ Yao et al. (2006): Particle listings—Lambda
  14. ^ Yao et al. (2006): Particle listings—Charmed Lambda
  15. ^ Yao et al. (2006): Particle listings—Bottom Lambda
  16. ^ Yao et al. (2006): Particle listings—Positive Sigma
  17. ^ Yao et al. (2006): Particle listings—Neutral Sigma
  18. ^ Yao et al. (2006): Particle listings—Negative Sigma
  19. ^ a b c Yao et al. (2006): Particle listings—Charmed Sigma(2455)
  20. ^ a b Aaltonen et al. (2007a)
  21. ^ Yao et al. (2006): Particle listings—Neutral Xi
  22. ^ Yao et al. (2006): Particle listings—Negative Xi
  23. ^ a b c d Yao et al. (2006): Particle listings—Charmed baryons
  24. ^ Yao et al. (2006): Particle listings—Double charmed positive Xi
  25. ^ a b Yao et al. (2006): Particle listings—Bottom Xis
  26. ^ Abazov et al. (2007)
  27. ^ Aaltonen et al. (2007b)
  28. ^ Yao et al. (2006): Particle listings—Charmed Omega
  29. ^ a b c d Yao et al. (2006): Particle listings—Delta(1232)
  30. ^ a b c d Physics Particle Overview — Baryons. Retrieved on 2008-04-20.
  31. ^ a b c Yao et al. (2006): Particle listings—Sigma(1385)
  32. ^ a b c Yao et al. (2006): Particle listings—Charmed Sigma(2520)
  33. ^ a b Yao et al. (2006): Particle listings—Xi(1530)
  34. ^ a b Yao et al. (2006): Particle listings—Charmed Xi(2645)
  35. ^ Yao et al. (2006): Particle listings—Negative Omega
  36. ^ Yao et al. (2006): Particle listings—Neutral Charmed Omega(2770)
  37. ^ Yao et al. (2006): Particle listings—Positive Theta
  38. ^ Yao et al. (2006): Particle listings—Charmed Theta
  39. ^ Yao et al. (2006): Particle listings—Phi(1860)

[edit] References

[edit] Further reading

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Particles in physics
Elementary particles
Composite particles
Hadrons:  Baryons/Hyperons/Nucleons: p+ · n0 · Δ · Λ · Σ · Ξ · Ω • Mesons/Quarkonia: π · K · ρ · J/ψ · Υ
Other:  Atomic nuclei • Atoms • Exotic atoms: Positronium · Muonium • Molecules
Hypothetical elementary particles
Hypothetical composite particles
Quasiparticles
Lists