Properties of glueballs Glueball

1 properties of glueballs

1.1 constituent particles , color charge
1.2 total angular momentum
1.3 electric charge
1.4 mass , parity
1.5 stability , decay channels

properties of glueballs

in principle, theoretically possible properties of glueballs calculated , derived directly equations , fundamental physical constants of quantum chromodynamics (qcd) without further experimental input. so, predicted properties of these hypothetical particles can described in exquisite detail using standard model physics have wide acceptance in theoretical physics literature. but, there considerable uncertainty in measurement of of relevant key physical constants, , qcd calculations difficult solutions these equations numerical approximations (reached several different methodologies). can lead variation in theoretical predictions of glueball properties mass , branching ratios in glueball decays.

constituent particles , color charge

theoretical studies of glueballs have focused on glueballs consisting of either 2 gluons or 3 gluons, analogy mesons , baryons have 2 , 3 quarks respectively. in case of mesons , baryons, glueballs qcd color charge neutral. baryon number of glueball zero.

total angular momentum

two gluon glueballs can have total angular momentum (j) of 0 (which scalar or pseudo-scalar) or 2 (tensor). 3 gluon glueballs can have total angular momentum (j) of 1 (vector boson) or 3. glueballs have integer total angular momentum implies bosons rather fermions.

glueballs particles predicted standard model total angular momentum (j) (sometimes called intrinsic spin ) either 2 or 3 in ground states, although mesons made of 2 quarks j=0 , j=1 similar masses have been observed , excited states of other mesons can have these values of total angular momentum.

fundamental particles ground states having j=0 or j=2 distinguished glueballs. hypothetical graviton, while having total angular momentum j=2 massless , lack color charge, , distinguished glueballs. standard model higgs boson experimentally measured mass of 125–126 gev/c² has been determined fundamental particle j=0 in standard model. lacks color charge , hence not engage in strong force interactions. higgs boson 25–80 times heavy mass of various glueball states predicted standard model.

electric charge

all glueballs have electric charge of 0 gluons not have electric charge.

mass , parity

glueballs predicted quantum chromodynamics massive, notwithstanding fact gluons have 0 rest mass in standard model. glueballs 4 possible combinations of quantum numbers p (parity) , c (c-parity) every possible total angular momentum have been considered, producing @ least fifteen possible glueball states including excited glueball states share same quantum numbers have differing masses lightest states having masses low 1.4 gev/c (for glueball quantum numbers j=0, p=+, c=+), , heaviest states having masses great 5 gev/c (for glueball quantum numbers j=0, p=+, c=-).

these masses on same order of magnitude masses of many experimentally observed mesons , baryons, masses of tau lepton, charm quark, bottom quark, hydrogen isotopes, , helium isotopes.

stability , decay channels

just standard model mesons , baryons, except proton, unstable in isolation, glueballs predicted standard model unstable in isolation, various qcd calculations predicting total decay width (which functionally related half-life) various glueball states. qcd calculations make predictions regarding expected decay patterns of glueballs. example, glueballs not have radiative or 2 photon decays, have decays pairs of pions, pairs of kaons, or pairs of eta mesons.