Hadrons are subatomic particles of a type including baryons and mesons that can take part in the strong interaction and may be useful in radiation astronomy. The eight toroid magnets can be seen surrounding the calorimeter that is later moved into the middle of the detector. Credit: Maximilien Brice.{{free media}}

At right a person works lower center left in front of the huge ATLAS detector, one of six detectors attached to the Large Hadron Collider at CERN.

Def. a strongly interacting particle or a particle which is affected by the strong nuclear force is called a hadron.

Here's a theoretical definition:

## Strong interactions

The strong interaction is observable in two areas: on a larger scale (about 1 to 3 femtometers (fm)), it is the force that binds protons and neutrons (nucleons) together to form the nucleus of an atom. On the smaller scale (less than about 0.8 fm, the radius of a nucleon), it is also the force that forms and holds together protons, neutrons and other hadron particles.

In the context of binding protons and neutrons together to form atoms, the strong interaction is called the nuclear force (or residual strong force). The strong interaction obeys a quite different distance-dependent behavior between nucleons.

Unlike the electromagnetic and weak interactions, the strong force does not diminish in strength with increasing distance. After a limiting distance (about the size of a hadron) has been reached, it remains at a strength of about 10,000 newtons, no matter how much farther the distance between hadrons. The force between hadrons remains constant at any distance after the hadrons travel only a tiny distance from each other, and is equal to that needed to raise one ton, which is 1000 kg x 9.8 N = ~ 10,000 N.

The amount of work done against a force of 10,000 newtons (about the weight of a one-metric ton mass on the surface of the Earth) is enough to create particle-antiparticle pairs within a very short distance of an interaction.

The strong force is nearly absent between such hadrons (i.e., between baryons or mesons). In this case, only a residual force called the residual strong force acts between these hadrons, and this residual force diminishes rapidly with distance, and is thus very short-range (effectively a few femtometers).

## Cosmic rays

Differential energy spectrum shows the differential vertical hadron intensity versus hadron energy in GeV. Credit: F. Ashton, A. Nasri, & I. A. Ward.{{fairuse}}

The "problems plaguing (3 + 1)- dimensional quantum gravity quantization programs are solved by virtue of the fact that spacetime is dimensionally-reduced. Indeed, effective models of quantum gravity are plentiful in (2 + 1) and even (1 + 1) dimensions [11–13]. Similarly, the cosmological constant problem may be explained as a Casimir-type energy between two adjacent “foliations” of three-dimensional space as the scale size L > L4 opens up a fourth space dimension."

"What makes this proposal of evolving dimensions very attractive is that some evidence of the lower dimensional structure of our space-time at a TeV scale may already exist. Namely, alignment of the main energy fluxes in a target (transverse) plane has been observed in families of cosmic ray particles [18–20]. The fraction of events with alignment is statistically significant for families with energies higher than TeV and large number of hadrons. This can be interpreted as evidence for coplanar scattering of secondary hadrons produced in the early stages of the atmospheric cascade development."

In the image on the right, the "energy spectrum of hadrons in cosmic rays at sea level has been measured over the energy range 600 GeV - 8 TeV. The spectrum is found to be well represented in differential form by N(E)dE = AE-𝛄dE where 𝛄 = 2.74 ± 0.16 with no suggested anomalous behaviour over the whole energy range."

"Incident hadrons either interact in the lead (15 cm thick) or iron (15 cm thick) targets and the resulting cascade traverses the plastic scintillators [...] which are both 5 cm thick. Using a burst of size > 400 equivalent muons traversing either scintillator as a master trigger a high voltage pulse was applied to the flash tubes, which are photographed, after a time delay of 330 𝛍s. From the resulting photograph the projected angle of incidence of the incident hadron could be determined and a decision taken a to whether is was in the acceptance geometry as defined [...]. [...] In converting the burst spectrum measurements to an estimate of the incident hadron spectrum the hadrons have been assumed to be nucleons. If charged pions are assumed the energies shown in [the image on the right] should be reduced by 0.8."

A hadron, like an atomic nucleus, is a composite particle held together by the strong force. Hadrons are categorized into two families: baryons (such as protons and neutrons) and mesons.

Def. a "composite particle [...] held together by the strong force and (consequently) can interact with other particles via said force; a meson or a baryon" is called a hadron.

The "fact that the regime of (star-relevant) high densities and low temperatures cannot be accessed by lattice or perturbative calculations makes the quark matter EoS even less constrained than the hadronic one, where at least there is some information on ground state matter properties."

"Hybrid stars have been applied to investigate a broad range of topics regarding compact stars, such as nucleation in hadronic matter [24, 41, 42], color superconductivity in quark matter [22–26], stability [22, 43, 44], rotation of neutron stars [43, 45–51], magnetic neutrons stars [52–55], thermal evolution [56–59], proto-neutron stars [60–62], supernovae [27, 63], radial oscillations [44, 64, 65], etc. The deconfinement phase transition has been extensively studied with different models such as Nambu-Jona-Lasinio [28, 61, 66–72], MIT bag model [23, 44, 55, 73–76], quark-meson coupling models [9, 72, 77, 78], and other approaches [58, 79–84], showing that the features of the models used to describe both phases have implications for the determination of the macroscopic properties and composition of stars."

"The hadronic phase (with nucleons, hyperons and leptons) is described by the many-body forces model (MBF model), which simulates the effects of many-body forces via non-linear scalar fields contributions in the effective coupling ."

"The many-body forces (MBF) model  is a relativistic mean field model in which meson field dependences are introduced in the couplings of baryons to mesons."

The "introduction of hyperons in a hadronic model softens drastically the EoS of hadronic matter, generating a sequence of stars with much smaller maximum mass, as discussed several times on literature. For the same reason, as hyperons start to populate the core of stars, for masses above 1.5M, the stars become more compact, i.e., present a smaller radius. Similarly, comparting hadronic stars [...] to all hybrid ones (all others), one can see a reduction in radius of 14.44 km to 12.32 km (Set 6) for the 1.4 M star, for example."

"For the corresponding stars modeled in a Maxwell construction [...], the phase transition takes place for chemical potentials higher than the ones in a Gibbs construction, and consequently the gap between critical and maximum masses is smaller. For this case, stars are mostly hadronic, containing only a small quark core. In particular, the critical and maximum masses are the same [...], indicating that all stars in this family are hadronic [...], as the phase transition never takes place for stable stars."

"For the 1.4M star, [...] one can see that the difference in radius can vary by more than 2 km when comparing hadronic and hybrid stars."

## Hyperons

A combination of three u, d or s-quarks with a total spin of 3/2 form the so-called baryon decuplet. The lower six are hyperons. Credit: Wierdw123.

A hyperon is any baryonic form of matter that may exist in a stable form within the core of some neutron stars.

"The impact of exotic compositions on the structure of isolated neutron stars has been studied in the past for stars composed of hyperons [1–9], Delta baryon resonances [10–14], meson condensates [15–21], quarks or even color superconducting quark matter [22–26]. Such degrees of freedom are usually associated with a softening of the equation of state (EoS), impacting the maximum mass and stability of stars [27, 28]."

"When hyperons are taken into account in relativistic mean field models, especial attention must be given to the hyperon-hyperon interaction modeling due to their internal strangeness degree of freedom. This is done through the introduction of φ and σ mesons, which mediate the interaction among these particles by describing repulsion and attraction features, respectively . The competition between softness and stiffness of the EoS due to the presence of hyperons has been widely discussed in the literature under the name of hyperon puzzle [2–4, 7, 8, 30– 36]."

"The MBF model reproduces both nuclear matter prop- erties at saturation and the observational properties of neutron stars with hyperons  and magnetic hybrid stars [55, 131].""

Here's a theoretical definition:

Def. any hadron that can decompose into another hadron or baryons is called a hyperon.

Hyperons
Particle Symbol Makeup Rest mass
electron volt MeV/speed of light c2
Isospin
Isospin I
Spin (physics) Spin(Parity (physics) Parity)
Spin (physics) JParity (physics) P
charge (physics) Q strangeness S charm (quantum number) C bottomness B' Mean lifetime
second s
class=unsortable Commonly decays to
Lambda  Λ0
uds 1 115.683(6) 0 12+ 0 −1 0 0 2.60×1010

p+
+ π

or n0
+ π0
Sigma  Σ+
uus 1 189.37(0.7) 1 12+ +1 −1 0 0 8.018±0.026×1011
p+
+ π0

or n0
+ π+
Sigma  Σ0
uds 1 192.642(24) 1 12+ 0 −1 0 0 7.4±0.7×1020
Λ0
+ γ
Sigma  Σ
dds 1 197.449(30) 1 12+ −1 −1 0 0 1.479±0.011×1010
n0
+ π
Sigma resonance  Σ∗+
(1385)
uus 1 382.8(4) 1 32+ +1 −1 0 0 Λ + π or
Σ + π
Sigma resonance  Σ∗0
(1385)
uds 1 383.7±1.0 1 32+ 0 −1 0 0 Λ + π or
Σ + π
Sigma resonance  Σ∗−
(1385)
dds 1 387.2(5) 1 32+ −1 −1 0 0 Λ + π or
Σ + π
Xi  Ξ0
uss 1 314.83(20) 12 12+ 0 −2 0 0 2.90±0.09×1010
Λ0
+ π0
Xi  Ξ
dss 1 321.31(13) 12 12+ −1 −2 0 0 1.639±0.015×1010
Λ0
+ π
Xi resonance  Ξ∗0
(1530)
uss 1 531.80(32) 12 32+ 0 −2 0 0 Ξ + π
Xi resonance  Ξ∗−
(1530)
dss 1 535.0(6) 12 32+ −1 −2 0 0 Ξ + π
Omega Ω
sss 1 672.45(29) 0 32+ −1 −3 0 0 8.21±0.11×1011
Λ0
+ K
or
Ξ0
+ π
or

Ξ
+ π0

Notes:

• Since strangeness is conserved by the strong interactions, the ground-state hyperons cannot decay strongly. However, they do participate in strong interactions.
• Λ0
may also decay on rare occurrences via these processes:
Λ0
p+
+ e
+ ν
e
Λ0
p+
+ μ
+ ν
μ
• Ξ0
and Ξ
are also known as "cascade" hyperons, since they go through a two-step cascading decay into a nucleon.
• The Ω
has a baryon number of +1 and hypercharge of −2, giving it strangeness of −3.

## Baryons

A baryon is a composite subatomic particle bound together by the strong interaction, whereas leptons are not. The most familiar baryons are the protons and neutrons that make up most of the mass of the visible matter in the universe. Electrons (the other major component of the atom) are leptons. Each baryon has a corresponding antiparticle (antibaryon).

Baryonic matter is matter composed mostly of baryons (by mass), which includes atoms of any sort (and thus includes nearly all matter that may be encountered or experienced in everyday life).

Def. a composite subatomic particle bound together by the strong interaction is called a baryon.

## Antineutrons

Def. the "antiparticle corresponding to a neutron" is called an antineutron.

## Nucleons

Def. one "of the subatomic particles of the atomic nucleus, i.e. a proton or a neutron" is called a nucleon.

"The detection of GW170817 and its electromagnetic counterparts [AT2017gfo] allows us to constrain the equation of state of dense matter [...] Very stiff equations of state are ruled out by the upper limit on the average tidal deformability, ${\tilde {\rm {\Lambda }}}\lesssim 800$ , imposed by the detected gravitational wave signal." "By using several microscopic nucleonic equations of state, we first confirm the existence of a monotonic relation between R1.5 (the radius of the 1.5 M configuration) and [average tidal deformability] ${\tilde {\rm {\Lambda }}}$ ."

"In the twin-stars scenario, the low-mass objects are made of nucleons and have large radii and large Λ, while the most massive stars are hybrid stars with a very large quark content and small radii and Λ."

The "twin-stars configuration features a very large difference between the radii of the two components: (R1, R2) = (10.7, 13.0) km, which allows one to achieve concurrently a very small radius R1 and a sufficiently large ${\tilde {\rm {\Lambda }}}\approx 600$ ."

"While the standard interpretation of the GW170817 event in the one-family scenario is perfectly compatible with the merging of two nucleonic [neutron stars] NSs governed by a microscopic nuclear EOS respecting the MTOV > 2 M limit, [...] the lower limit on the tidal deformability obtained by Radice et al. (2018) is not incompatible with R1.5 being even significantly smaller than 12 km if one assumes that the population of compact stars is not made of only one family. [When] allowing for the existence of disconnected branches in the mass–radius relation, either within the two-families scenario or within the twin-stars scenario, one can explain the existence of very compact stars and at the same time one can fulfill the request of having a not too small average tidal deformability, as suggested by the analysis of AT2017gfo."

In "both scenarios, the source of GW170817 is a mixed binary system: a [hadronic star] HS and a [quark star] QS within the two-families scenario (Drago & Pagliara 2018) and a hybrid star and a nucleonic star within the twin-stars scenario (Paschalidis et al. 2018). It is interesting to note that within the two-families scenario, a system with the chirp mass of the source of GW170817 cannot be composed of two HSs: such a system would have too small an average tidal deformability, and moreover it would lead to a prompt collapse (Drago & Pagliara 2018)."

## Neutrons

Def. a "subatomic particle forming part of the nucleus of an atom and having no charge" is called a neutron.

"Due to the very low energy of the colliding protons in the Sun, only states with no angular momentum (s-waves) contribute significantly. One can consider it as a head-on collision, so that angular momentum plays no role. Consequently, the total angular momentum is the sum of the spins, and the spins alone control the reaction. Because of Pauli's exclusion principle, the incoming protons must have opposite spins. On the other hand, in the only bound state of deuterium, the spins of the neutron and proton are aligned. Hence a spin flip must take place [...] The strength of the nuclear force which holds the neutron and the proton together depends on the spin of the particles. The force between an aligned proton and neutron is sufficient to give a bound state, but the interaction between two protons does not yield a bound state under any circumstances. Deuterium has only one bound state."

The "force acting between the protons and the neutrons [is] the strong force".

"A potential of 36 MeV is needed to get just one energy state."

The width of a bound proton and neutron is "2.02 x 10-13 cm".

"Another possibility [regarding neutron stars, called "baryon matter",] is that in the absence of gravity high-density baryonic matter is bound by purely strong forces. [...] nongravitationally bound bulk hadronic matter is consistent with nuclear physics data [...] and low-energy strong interaction data [...] The effective field theory approach has many successes in nuclear physics [...] suggesting that bulk hadronic matter is just as likely to be a correct description of matter at high densities as conventional, unbound hadronic matter."

"The idea behind baryon matter is that a macroscopic state may exist in which a smaller effective baryon mass inside some region makes the state energetically favored over free particles. [...] This state will appear in the limit of large baryon number as an electrically neutral coherent bound state of neutrons, protons, and electrons in β-decay equilibrium."

## Antiprotons

Def. the "antiparticle of the proton, having a negative electric charge" is called an antiproton.

The antiproton (p, pronounced p-baer) is the antiparticle of the proton. Antiprotons are stable, but they are typically short-lived since any collision with a proton will cause both particles to be annihilated in a burst of energy.

Antiprotons have been detected in cosmic rays for over 25 years, first by balloon-borne experiments and more recently by satellite-based detectors. The standard picture for their presence in cosmic rays is that they are produced in collisions of cosmic ray protons with nuclei in the interstellar medium, via the reaction, where A represents a nucleus:

p + A → p + p + p + A

The secondary antiprotons (p) then propagate through the galaxy, confined by the galactic magnetic fields. Their energy spectrum is modified by collisions with other atoms in the interstellar medium. The antiproton cosmic ray energy spectrum is now measured reliably and is consistent with this standard picture of antiproton production by cosmic ray collisions.

## Protons

A "new type of neutron star model (Q stars) [is such that] high-density, electrically neutral baryonic matter is a coherent classical solution to an effective field theory of strong forces and is bound in the absence of gravity. [...] allows massive compact objects, [...] and has no macroscopic minimum mass."

"Compact objects in astronomy are usually analyzed in terms of theoretical characteristics of neutron stars or black holes that are based upon calculations of equations of state for matter at very high densities. At such high densities, the effects of strong forces cannot be neglected. There are several conventional approaches to describing nuclear forces, all of which find that for a baryon number greater than ~250, a nucleus will become energetically unbound. High-density hadronic matter is not stable in these theories until there are enough baryons for gravitational binding to form a neutron star, typically with a minimum mass ≳ 0.1 M and maximum mass ≲ 3 M."

Def. a "positively charged [subatomic] particle forming part of the nucleus of an atom and determining the atomic number of an element" is called a proton.

## Mesons

Def. a composite subatomic particle bound together by the strong interaction "intermediate between electrons and protons" is called a meson.

Because mesons are composed of sub-particles, they have a physical size, with a radius roughly one femtometre, which is about 2/3 the size of a proton or neutron. All mesons are unstable, with the longest-lived lasting for only a few hundredths of a microsecond. Charged mesons decay (sometimes through intermediate particles) to form electrons and neutrinos. Uncharged mesons may decay to photons.

Mesons are not produced by radioactive decay, but appear in nature only as short-lived products of very high-energy interactions in matter. In cosmic ray interactions, for example, such particles are ordinary protons and neutrons. Mesons are also frequently produced artificially in high-energy particle accelerators that collide protons, anti-protons, or other particles.

In nature, the importance of lighter mesons is that they are the associated quantum-field particles that transmit the nuclear force, in the same way that photons are the particles that transmit the electromagnetic force.

Each type of meson has a corresponding antiparticle (antimeson) in which quarks are replaced by their corresponding antiquarks and vice-versa.

Mesons are subject to both the weak and strong interactions. Mesons with net electric charge also participate in the electromagnetic interaction.

While no meson is stable, those of lower mass are nonetheless more stable than the most massive mesons, and are easier to observe and study in particle accelerators or in cosmic ray experiments. They are also typically less massive than baryons, meaning that they are more easily produced in experiments, and thus exhibit certain higher energy phenomena more readily than baryons composed of the same quarks would.

## B mesons

Comparison of the LHCb data on B0 meson production, both for central and for forward rapidities, with the theoretical predictions from POWHEG and aMC@NLO. Credit: Rhorry Gauld, Juan Rojo, Luca Rottoli and Jim Talbert.{{fairuse}}

"The K0-K0 bar, D0-D0 bar, and B0-B0 bar oscillations are extremely sensitive to the K0 and K0 bar energy at rest. The energy is determined by the values mc2 with the related mass as well as the energy of the gravitational interaction. Assuming the CPT theorem for the inertial masses and estimating the gravitational potential through the dominant contribution of the gravitational potential of our Galaxy center, we obtain from the experimental data on the K0-K0 bar oscillations the following constraint: |(mg/mi)K0 - (mg/mi)K0 bar| ≤ 8·10-13, CL=90%. This estimation is model dependent and in particular it depends on a way we estimate the gravitational potential. Examining the K0-K0 bar, B0-B0 bar, and D0-D0 bar oscillations provides us also with weaker, but model independent constraints, which in particular rule out the very possibility of antigravity for antimatter."

"In spite of the apparent parity non-invariance of the ordinary particles, the universe could still be left-right symmetric if [charge conjugation parity] CP were an exact symmetry. But this option is [...] ruled out by experiments on kaons and B-mesons!)."

In the graphs on the right, the Large Hadron Collider beauty (LHCb) detector data for the production of B0 mesons, both for central and for forward rapidities, by pp collisions is compared with the theoretical predictions from the Positive Weight Hardest Emission Generator (POWHEG) and the automation of Monte Carlo (MC) at next-to-leading order (NLO) (aMC@NLO).

"The indicated theory uncertainty band includes only the scale uncertainties, and we have verified that parton distribution function (PDF) uncertainties are not so relevant in this case. As in the case of charm, satisfactory agreement between theory and data for B meson production in the forward region is found."

## Psions

On the right is a graph of the production of psi mesons (psions) at Fermilab.

The "discovery of the psi meson in 1974, independently by Samuel C.C. Ting and Burton Richter [22, 23] [pointed out] its lifetime, which was about a thousand times longer than any other similar particle’s lifetime."

The "SLAC-LBL group looked between a pair of 100-MeV "milestones" and discovered the extremely narrow psi resonance that sent the counting rate up by more than a factor of 100, within the space of 1 MeV and within an observing time interval of 2 hours."

## D mesons

Comparison of GM-VFNS predictions with experimental data on open D0 (D0
) and D±
production in pp collisions collected by the ALICE Collaboration at √S = 7 TeV. Credit: Michael Benzke, Maria V. Garzelli and Bernd A. Kniehl.{{fairuse}}

In the graphs on the right are comparisons of general-mass variable-flavor-number scheme (GM-VFNS) predictions with experimental data on open D0 (D0
) and D±
production in pp collisions collected by the A Large Ion Collider Experiment (ALICE) Collaboration at the Large Hadron Collider at CERN at √S = 7 TeV. These data represent likely fluxes arising from the decay of pp collisions produced by the interactions of high-energy cosmic rays in the Earth’s atmosphere.

$D_{S}\rightarrow \tau +{\bar {\nu }}_{\tau }\rightarrow \nu _{\tau }+{\bar {\nu }}_{\tau }.$ 
D mesons
Particle name Particle
symbol
Antiparticle
symbol
Rest mass (MeV/speed of light|c2) IG JPC S C B' Mean lifetime (s) Commonly decays to

(>5% of decays)

D meson
D+

D
1,869.62 ± 0.20 12 0 0 +1 0 1.040 ± 0.007 × 10−12 See
D+
decay modes
D meson
D0

D0
1,864.84 ± 0.17 12 0 0 +1 0 4.101 ± 0.015 × 10−13 See
D0
decay modes
Strange D meson
D+
s

D-
s
1968.47±0.33 0 0 +1 +1 0 (5.00±0.07) x 10-13 See
D+
s
decay modes
D meson
D∗+
(2010)

D∗−
(2010)
2,010.27.62 ± 0.17 12 1 0 +1 0 6.9 ± 1.9 × 10−21[a]
D0
+ π+ or

D+
+ π0
D meson
D∗0
(2007)

D∗0
(2007)
2,006.97 ± 0.19 12 1 0 +1 0 >3.1 × 10−22[a]
D0
+ π0 or

D0
+ γ

[a] PDG reports the resonance width (Γ). Here the conversion τ = ​ħΓ is given instead.

## Xis

Ξ0 has a rest mass of 1314.86 ± 0.20 MeV/c2.

Ξ has a rest mass of 1321.71 ± 0.07 MeV/c2.

Ξ0
b
has a rest mass of 5787.8 ± 5.0 ± 1.3 MeV/c2.

Xi baryons
class=unsortable Particle Symbol Makeup Rest mass
electron volt MeV/speed of light c2
Isospin
Isospin I
Spin (physics) Spin (Parity (physics) parity)
Spin (physics) JParity (physics) P
charge (physics) Q strangeness S charm (quantum number) C bottomness B Mean lifetime
second s
class=unsortable Decays to
Xi  Ξ0
uss 1314.86±0.20 1/2 1/2+* 0 −2 0 0 2.90±0.09×1010
Λ0
+ π0
Xi  Ξ
dss 1321.71±0.07 1/2 1/2+* −1 −2 0 0 1.639±0.015×1010
Λ0
+ π
Xi resonance  Ξ0
(1530)
uss 1531.80±0.32 1/2 3/2+ 0 −2 0 0 Ξ + π
Xi resonance  Ξ
(1530)
dss 1535.0±0.6 1/2 3/2+ −1 −2 0 0 Ξ + π
charmed Xi Ξ+
c
usc 2467.9±0.4 1/2 1/2* +* +1 −1 +1 0 4.42±0.26×1013
See Ξ+
c
Decay Modes
charmed Xi Ξ0
c
dsc 2471.0±0.4 1/2 1/2* +* 0 −1 +1 0 1.12++0.13
0.10
×1013
See Ξ0
c
Decay Modes
charmed Xi resonance  Ξ′+
c
usc 2575.7±3.1 1/2 1/2+[a] +1 −1 +1 0 Ξ+
c
+ γ (Seen)
charmed Xi resonance  Ξ′0
c
dsc 2578.0±2.9 1/2 1/2+[a] 0 −1 +1 0 1.1×1013
Ξ0
c
+ γ (Seen)
Ξcc++ double charmed Xi Ξ++
cc
ucc 3621.40 ± 0.72 ± 0.27 ± 0.14 1/2* 1/2* +* +2 0 +2 0 $0.256_{-0.022}^{+0.024}$ ±0.014×10−12  Λ+
c
+ K
+ π+
+ π+
double charmed Xi[b]  Ξ+
cc
dcc 3518.9±0.9[b] 1/2* 1/2* +* +1 0 +2 0 <3.3×1014
[b]
Λ+
c
+ K
+ π+
[e] or
p+
+ D+
+ K
[e]
bottom Xi  Ξ0
b
usb 5792±3 1/2* 1/2* +* 0 −1 0 −1 1.42++0.28
0.24
×1012
[c]
See Ξ
b
Decay Modes
bottom Xi or
Ξ
b
dsb 5792.9±3.0 1/2* 1/2* +* −1 −1 0 −1 1.42×1012
See Ξ
b
Decay Modes

(Ξ
+ J/ψ
was also seen)
Ξ′
b

dsb 5935.02 ± 0.02 ± 0.01± 0.50 1/2+ −1 −1 0 −1
Ξ∗−
b

dsb 5955.33 ± 0.12 ± 0.06 ± 0.50 3/2+ −1 −1 0 −1
Ξ
b
(6227)
dsb 6226.9 ± 2.0 ± 0.3 ± 0.2 −1 −1 0 −1 Λ
b
+ K

Ξ0
b
+ π
double bottom Xi[a] Ξ0
bb
ubb 1/2* 1/2* +* 0 0 0 −2
double bottom Xi[a] Ξ
bb
dbb 1/2* 1/2* +* −1 0 0 −2
charmed bottom Xi[a] Ξ+
cb
ucb 1/2* 1/2* + +1 0 +1 −1
charmed bottom Xi[a] Ξ0
cb
dcb 1/2* 1/2* +* 0 0 +1 −1
1. Particle (or quantity, i.e. spin) has neither been observed nor indicated
3. 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 Ξ
b
, with some Λ
b
.

## Sigmas

Σ+ has a rest mass of 1189.37 ± 0.07 MeV/c2.

Σ0 has a rest mass of 1192.642 ± 0.024 MeV/c2.

Σ
b
has a rest mass of 5815.5 +0.6 −0.5 ± 1.7 MeV/c2.

The symbols encountered in these lists are: I (isospin), J (total angular momentum), P (parity (physics)|parity), u (up quark), d (down quark), s (strange quark), c (charm quark), t (top quark), b (bottom quark), Q (electric charge), S (strangeness), C (charmness), B′ (bottomness), T (topness), as well as other subatomic particles (hover for name).

Antiparticles are not listed in the table; however, they simply would have all quarks changed to antiquarks (and vice versa), and Q, B, S, C, B′, T, would be of opposite signs. I, J, and P values in red have not been firmly established by experiments, but are predicted by the quark model and are consistent with the measurements.

### JP = 1/2+ Sigma baryons

JP = 1/2+ Sigma baryons
Particle name Symbol Quark
content
MeV/speed of light|c2) Isospin|I Total angular momentum|JParity (physics)|P charge (physics)|Q (elementary charge|e) strangeness|S charm (quantum number)|C bottomness|B' topness|T s) Commonly decays to
Sigma Σ+
uus 1,189.37 ± 0.07 1 1/2+ +1 −1 0 0 0 8.018 ± 0.026 × 10−11 p+
+ π0
or

n0
+ π+

Sigma Σ0
uds 1,192.642 ± 0.024 1 1/2+ 0 −1 0 0 0 7.4 ± 0.7 × 10−20 Λ0
+ γ
Sigma Σ
dds 1,197.449 ± 0.030 1 1/2+ −1 −1 0 0 0 1.479 ± 0.011 × 10−10 n0
+ π
charmed Sigma Σ++
c
(2455)
uuc 2,454.02 ± 0.18 1 1/2 + +2 0 +1 0 0 3.0 ± 0.4 × 10−22[a] Λ+
c
+ π+
charmed Sigma Σ+
c
(2455)
udc 2,452.9 ± 0.4 1 1/2 + +1 0 +1 0 0 >1.4 × 10−22[a] Λ+
c
+ π0
charmed Sigma Σ0
c
(2455)
ddc 2,453.76 ± 0.18 1 1/2 + 0 0 +1 0 0 3.0 ± 0.5 × 10−22[a] Λ+
c
+ π
bottom Sigma Σ+
b
uub 5,807.7 ± 3.8 1 1/2 + +1 0 0 −1 0 Unknown Λ0
b
+ π+
(seen)
bottom Sigma Σ0
b
udb Unknown 1 1/2 + 0 0 0 −1 0 Unknown Unknown
bottom Sigma Σ
b
ddb 5,815.2 ± 2.7 1 1/2 + −1 0 0 −1 0 Unknown Λ0
b
+ π
(seen)
Top Sigma Σ++
t
uut 1 1/2 + +2 0 0 0 +1
Top Sigma Σ+
t
udt 1 1/2 + +1 0 0 0 +1
Top Sigma Σ0
t
ddt 1 1/2 + 0 0 0 0 +1

The standard model predicts that this particle cannot exist due to the short lifetime of the top quark.
[a] PDG reports the resonance width (Γ). Here the conversion τ = ħ/Γ is given instead.
[b] The specific values of the name has not been decided yet, but will likely be close to Σ
b
(5810).

### JP = 3/2+ Sigma baryons

JP = 3/2+ Sigma baryons
Particle name Symbol Quark
content
MeV/speed of light|c2) Isospin|I Total angular momentum|JParity (physics)|P charge (physics)|Q (elementary charge|e) strangeness|S charm (quantum number)|C bottomness|B' topness|T s) Commonly decays to
Sigma Σ∗+
(1385)
uus 1,382.8 ± 0.4 1 3/2+ +1 −1 0 0 0 1.84 ± 0.04 × 10−23[c] Λ0
+ π+
or

Σ+
+ π0
or

Σ0
+ π+

Sigma Σ∗0
(1385)
uds 1,383.7 ± 1.0 1 3/2+ 0 −1 0 0 0 1.8 ± 0.3 × 10−23[c] Λ0
+ π0
or

Σ+
+ π
or

Σ0
+ π0

Sigma Σ∗−
(1385)
dds 1,387.2 ± 0.5 1 3/2+ −1 −1 0 0 0 1.67 ± 0.09 × 10−23[c] Λ0
+ π
or

Σ0
+ π
or

Σ
+ π0
or

charmed Sigma Σ∗++
c
(2520)
uuc 2,518.4 ± 0.6 1 3/2 + +2 0 +1 0 0 4.4 ± 0.6 × 10−23[c] Λ+
c
+ π+
charmed Sigma Σ∗+
c
(2520)
udc 2,517.5 ± 2.3 1 3/2 + +1 0 +1 0 0 >3.9 × 10−23[c] Λ+
c
+ π0
charmed Sigma Σ∗0
c
(2520)
ddc 2,518.0 ± 0.5 1 3/2 + 0 0 +1 0 0 4.1 ± 0.5 × 10−23[c] Λ+
c
+ π
bottom Sigma Σ∗+
b
uub Unknown 1 3/2 + +1 0 0 −1 0 Unknown Unknown
bottom Sigma Σ∗0
b
udb Unknown 1 3/2 + 0 0 0 −1 0 Unknown Unknown
bottom Sigma Σ∗−
b
ddb Unknown 1 3/2 + −1 0 0 −1 0 Unknown Unknown
Top Sigma Σ∗++
t
uut 1 3/2 + +2 0 0 0 +1
Top Sigma Σ∗+
t
udt 1 3/2 + +1 0 0 0 +1
Top Sigma Σ∗0
t
ddt 1 3/2 + 0 0 0 0 +1

The standard model predicts that this particle cannot exist due to the short lifetime of the top quark.
[c] PDG reports the resonance width (Γ). Here the conversion τ = ħ/Γ is given instead.

## Lambdas

Λ0 has a rest mass of 1115.683 ± 0.006 MeV/c2.

Λ+
c
has a rest mass of 2286.46 ± 0.146 MeV/c2.

On 13 July 2015, the LHCb collaboration at CERN reported results consistent with pentaquark states in the decay of bottom Lambda baryons (Λ0
b
).

Rest mass = 5619.4 ± 0.6 MeV/c2.

## Phi mesons

The phi meson $\Phi ^{0}$ (1020) has a mass of 1019.445 MeV. It decays per

1. $\Phi ^{0}\rightarrow \mathrm {K} ^{+}+\mathrm {K} ^{-}or$
2. $\Phi ^{0}\rightarrow \mathrm {K} _{S}^{0}+\mathrm {K} _{L}^{0}.$

"The scalar mesons σ and δ account for the description of attraction among baryons, while repulsion is described by the vector mesons ω, $\rho$  and $\phi$ ."

"The many-body forces (MBF) model  is a relativistic mean field model in which meson field dependences are introduced in the couplings of baryons to mesons."

The "$\phi$  mesons mediates interaction among hyperons, providing extra repulsion, which plays an important role in the description of massive stars with hyperon content ."

The "whole fundamental baryon octet (n, p, Σ, Σ0, Σ+, Λ, Ξ, Ξ0) [is exhausted] and simulates n‐order corrections to the minimal Yukawa couplings by considering many‐body nonlinear self‐couplings and meson–meson interaction terms involving scalar–isoscalar (σ, σ*), vector–isoscalar (ω, ϕ), vector–isovector (ϱ), and scalar–isovector (δ) sectors."

"The hidden mesons do not couple with nucleons, so g𝛔*N = g𝚽N = 0. [...] the following value for the delta meson-nucleon coupling constant (Bednarek 2003): gδN = 3.1 [is chosen]."

Advanced "Laser Interferometer Gravitational‐Wave Observatory (aLIGO) and Gravitational Wave Interferomenter of the European Gravitational Observatory (VIRGO) detectors measured a value of [the tidal deformability parameter] in the event GW170817 (Abbott 2017), and it has been noticed that the values of [the tidal deformability parameter] ≤ 800 in the low‐spin case and [the tidal deformability parameter] ≤ 700 in the high‐spin case are within the 90% credible interval."

Results suggest each baryon-meson coupling can by "predictions of the tidal parameter represent a useful constraint of the EoS of neutron stars."

## Omega mesons

"The detection of GW170817 and its electromagnetic counterparts allows us to constrain the equation of state of dense matter [... The] couplings [for equation of state (EoS) were set] with the omega and the rho meson to xωΔ = xρΔ = 1. [This choice is] motivated by several analyses of scattering data (electron and pion scattering off nuclei), suggesting a coupling with the sigma meson [is] stronger than the coupling with the omega meson [...]."

Omega meson production:

1. $p+d\rightarrow He^{3}+\omega ,$
2. ${\bar {p}}+p\rightarrow \omega +\eta +\pi _{0},$
3. $\pi ^{-}+p\rightarrow \omega +n,$
4. $p+{\bar {p}}\rightarrow \mathrm {K} ^{+}+\mathrm {K} ^{-}+\omega ,$
5. $p+{\bar {p}}\rightarrow \mathrm {K} 1+\mathrm {K} 1+\omega ,$

Omega meson ω(782) decay modes:

1. Γ1: $\omega \rightarrow \pi ^{+}+\pi ^{-}+\pi ^{0},$
2. Γ2: $\omega \rightarrow \pi ^{0}+\gamma ,$
3. Γ3: $\omega \rightarrow \pi ^{+}+\pi ^{-},$
4. Γ4: $\omega \rightarrow neutrals(excluding:\pi ^{0}+\gamma ),$
5. Γ5: $\omega \rightarrow \eta +\gamma ,$
6. Γ6: $\omega \rightarrow \pi ^{0}+e^{+}+e^{-},$
7. Γ7: $\omega \rightarrow \pi ^{0}+\mu ^{+}+\mu ^{-},$
8. Γ8: $\omega \rightarrow \eta +e^{+}+e^{-},$
9. Γ9: $\omega \rightarrow e^{+}+e^{-},$
10. Γ10: $\omega \rightarrow \pi ^{+}+\pi ^{-}+\pi ^{0}+\pi ^{0},$
11. Γ11: $\omega \rightarrow \pi ^{+}+\pi ^{-}+\gamma ,$
12. Γ12: $\omega \rightarrow \pi ^{+}+\pi ^{-}+\pi ^{+}+\pi ^{-},$
13. Γ13: $\omega \rightarrow \pi ^{0}+\pi ^{0}+\gamma ,$
14. Γ14: $\omega \rightarrow \eta +\pi ^{0}+\gamma ,$
15. Γ15: $\omega \rightarrow \mu ^{+}+\mu ^{-},$
16. Γ16: $\omega \rightarrow 3\gamma ,$
17. Γ17: $\omega \rightarrow \eta +\pi ^{0},$
18. Γ18: $\omega \rightarrow 2\pi ^{0},and$
19. Γ19: $\omega \rightarrow 3\pi ^{0}.$

## Rho mesons

Rho mesons occur in three states: ρ+, ρ-, and ρ0. The rest masses are apparently the same at 775.4±0.4 and 775.49±0.34. Decay products are π± + π0 or π+ + π-, respectively.

Def. a "short-lived hadronic isospin triplet" is called a rho meson.

With "a standard relativistic equation of state (GM3) [...] rho-meson condensates can appear in the core of the neutron star as the rho mass decreases with density and magnetic field. For reasonable values of the parameters, the rho condensate can appear in a neutron star at 4.4 times the normal nuclear matter density. This number guarantees a sizeable portion of the star to have a ρ-condensed phase."

## Kaons

"The muons created through decays of secondary pions and kaons are fully polarized, which results in electron/positron decay asymmetry, which in turn causes a difference in their production spectra."

The "highest energy neutrinos from GRBs mainly come from kaons."

## Sigma mesons

Two "parameterizations corresponding to two different values for the coupling of the delta resonances [are considered] with the sigma meson: xσΔ = 1.15 (SFHO+HD [(Drago et al. 2014b)]) and xσΔ = 1 (SFHO+HD2)[...] motivated by several analyses of scattering data (electron and pion scattering off nuclei) [...]."

## Pions

Single π0 production occurs "in neutral current neutrino interactions with water by a 1.3 GeV wide band neutrino beam."

"The Gamma-Ray Spectrometer (GRS) on [Solar Maximum Mission] SMM has detected [...] at least two of the flares have spectral properties >40 MeV that require gamma rays from the decay of neutral pions. [Pion] production can occur early in the impulsive phase as defined by hard X-rays near 100 keV."

Gamma-ray "emission matches remarkably well both the position and shape of the inner [supernova remnant] SNR shocked plasma. Furthermore, the gamma-ray spectrum shows a prominent peak near 1 GeV with a clear decrement at energies below a few hundreds of MeV as expected from neutral pion decay."

"If protons are accelerated by the shock wave of a supernova remnant, they could interact with the surrounding interstellar gas to produce short-lived particles called π0 mesons, which in turn would decay to produce γ-rays at very high, TeV, energies (1 TeV = 1012 electron volts)."

## Tauons

"For ultrahigh energies the neutrino spectrum at the detector is influenced by neutrino-nucleon interactions and tauon decays during the passage through the interior of the earth."

## Neutrinos

"Atmospheric neutrinos can interact with the detector producing also hadrons. The most probable of these reactions is the single pion production :"

$\nu _{\mu }+p\rightarrow \mu ^{-}+\pi ^{+}+p^{'}.$

"There is also a small loss due to inelastic hadronic interactions of the decay particles before they are stopped."

The "optical properties of mixtures of PXE [phenyl-o-xylylethane] and derivatives of mineral oils are under investigation ."

"Neutrino detection includes four remarkable reactions:"

1. Muon production νμ + N → μ + all gives an excellent tool to search for the discrete sources, since directions of UHE muon and neutrino coincide.
2. Resonant production of W-boson, νe + e → W → hadrons results in production of monoenergetic showers with energy E0 = $m_{W}^{2}$ /2me = 6.3 × 106 GeV. This reaction has a large cross-section.
3. Tau production in a detector, ντ + N → τ + hadrons, is characterised by time sequence of three signals: a shower from prompt hadrons, the Cherenkov light from τ and hadron shower from τ-decay. SuperGZK ντ are absorbed less in the Earth due to regeneration: absorbed ντ is converted into τ, which decays producing ντ again.
4. Z-bursts provide a signal from the space, caused by the resonant Z0 production on DM neutrinos, ν + νDM → Z0 → hadrons. The energy of the detected neutrino must be tremendous: E0 = ${\frac {m_{Z}^{2}}{2m_{\nu }}}=1.7\times 10^{13}{\frac {0.23eV}{m_{\nu }}}GeV.$

Non-accelerator neutrino sources "include objects with annihilation of DM (the Sun, Earth, cores of the galaxies), objects with the decays of superheavy DM particles (galactic halos) and topological defects. In the last two cases neutrinos are produced in the decays of superheavy particles with the masses up to MGUT ∼ 1016 GeV. A particle decays to virtual particles, partons, which are cascading due to QCD interaction, and at the confinement radius cascade partons are converted to hadrons, most of which are pions. Neutrinos are produced in pion decays with spectrum which can be approximately described at highest energies as dE/E2.

"The possibility of using radio telescopes to detect radiation from electron-photon and hadron cascades produced by interactions of neutrinos and other superhigh-energy (greater than about 10 to the 20th eV) particles with the moon and other celestial bodies is discussed. Existing radio telescopes are already theoretically capable of detecting such radiation. The detection threshold could be lowered by using antennas placed on satellites orbiting the moon or other planets. Special geostationary satellites could detect radio emissions from cascades produced by neutrinos in the Antarctic ice."

## Gravitationals

The "frequency of [Primary Gravitational Waves] PGWs that would be detectable is [...] ≈ 1.67 x 10-4 (T*/TeV) Hz, where [T* is the primordial temperature and this relationship] holds for g* ~ 102. When T* = 1 TeV, the frequency is 𝑓𝚲 ~ 10-4 Hz. This is well below the seismic limit of 𝑓 ~ 40 Hz on ground-based gravity wave interferometer experiments like LIGO or VIRGO , but sits precisely at the threshold of LISA's sensitivity range. [The] latter observatory is expected to probe a variety of early-universe phenomenology from the 100 GeV - 1000 TeV period ."

## Omegas

Ω0
c
has a rest mass of 2695.2 ± 1.7 MeV/c2.

Ω
b
has a rest mass of 6071 ± 40 MeV/c2.

Omega
class=unsortable Particle Symbol Quark
content
Rest mass
(electron volt MeV/speed of light c2)
Spin (physics) JParity (physics) P charge (physics) Q
(elementary charge e)
strangeness S charm (quantum number) C bottomness Mean lifetime
(second s)
class=unsortable Decays to
Omega Ω
sss 1672.45±0.29 3/2+ −1 −3 0 0 8.21±0.11×1011
Λ0
+ K
or
Ξ0
+ π
or
Ξ
+ π0

Charmed omega Ω0
c
ssc 2697.5±2.6 1/2+ 0 −2 +1 0 6.9±1.2×1014
See Ω0
c
Decay Modes
Bottom omega Ω
b
ssb 6054.4±6.8 1/2+ −1 −2 0 −1 1.13±0.53×1012
Ω
+ J/ψ
(seen)
Double charmed omega† Ω+
cc
scc 1/2+ +1 −1 +2 0
Charmed bottom omega† Ω0
cb
scb 1/2+ 0 −1 +1 −1
Double bottom omega† Ω
bb
sbb 1/2+ −1 −1 0 −2
Triple charmed omega† Ω++
ccc
ccc 3/2+ +2 0 +3 0
Double charmed bottom omega† Ω+
ccb
ccb 1/2+ +1 0 +2 −1
Charmed double bottom omega† Ω0
cbb
cbb 1/2+ 0 0 +1 −2
Triple bottom omega† Ω
bbb
bbb 3/2+ −1 0 0 −3

† Particle (or quantity, i.e. spin) has neither been observed nor indicated.

## Deltas

Δ++ has a rest mass of 1,232 ± 2 MeV/c2.

Δ+ has a rest mass of 1,232 ± 2 MeV/c2.

Δ0 has a rest mass of 1,232 ± 2 MeV/c2.

Δ has a rest mass of 1,232 ± 2 MeV/c2.

## Upsilon mesons

A plot of the invariant mass of muon pairs, the peak at about 9.5 GeV is due to the contribution of the Upsilon meson. Credit: Leon Lederman and the E288 collaboration, Fermilab.

The plot on the right shows a peak at about 9.5 GeV due to the Upsilon meson.

## Eta mesons

Eta mesons (547.863 ± 0.018 MeV) have the decay schemes:

1. η : $\eta \rightarrow \gamma +\gamma ,$
2. η : $\eta \rightarrow \pi ^{0}+\pi ^{0}+\pi ^{0},or$
3. η : $\eta \rightarrow \pi ^{+}+\pi ^{0}+\pi ^{-},$

Eta prime mesons (957.78 ± 0.06 MeV) have the decay schemes:

1. η' : $\eta ^{'}\rightarrow \pi ^{+}+\pi ^{-}+\eta or$
2. η' : $\eta ^{'}\rightarrow \pi ^{0}+\pi ^{0}+\gamma ,$

The charmed eta meson ηC(1S) has a rest mass of 2983.6 ± 0.7 MeV.

## Hypotheses

1. Hadrons can be used in astronomy to discern information about their sources.