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Upsilon full decay width? (and reference request)

The decays of 1S, 2S, 3S states of the $\Upsilon$ meson are according the particle data group surprisingly stable, but not as stable as a typical weak-only decay. Some electromagnetic decays, such as ...
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1answer
30 views

Is radiative decay the same the electromagnetic decay?

Question could be a duplicated of this one "Radiative" particle decay? An electromagnetic decay should be clearly one that involves at least a photon, either directly or producing a pair ...
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27 views

Covariant projection method - Meson bound states

I have seen many papers that discuss the production or decay of mesons ( quark bound states ) to make use of the covariant projection method where the product $\upsilon\bar{u}$ of the quark spinors ...
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0answers
34 views

Is there any difference in mixing and oscillation of neutral mesons?

I have often read about neutral Kaon oscillation or neutral B meson mixing. Both are described by the similar box diagrams. So I want to know if we can say neutral kaon mixing and D meson oscillation. ...
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0answers
39 views

Bound state of $\mu^- \mu^+$ . Why non-relativistic muon states?

Peskin & Schroeber page 148 discuss the creation of a $ \mu^+ \mu^-$ resonance state . Equation (5.44) describes the creation of a Spin Up bound $ \mu^+ \mu^-$: $$ \mathcal{M} = \sqrt{2M} \int ...
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0answers
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Isospin In Kaon Decay

The decay $ K \to \pi \pi $ at zero-strong interaction level is calculated by considering the matrix element of the operator $ Q_2 = (\bar{s}u)_{V-A} (\bar{u}d)_{V-A} $ for two kinds of processes: ...
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0answers
40 views

Mass and wave function renormalization In chiral perturbation theory

Before I put forward my actual question, I think it will be useful to set the context in a clear way and that involves my understanding of a few very basic things of Chiral Perturbation Theory. ...
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2answers
212 views

If mesons were stable could they form atoms?

if there were stable enough mesons similar to protons and neutrons could they capture electrons to form exotic elements. if not why is this not possible?
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0answers
30 views

What are the parity of particles? [duplicate]

When looking to see if particle collisions/decays are possible and what force they act through, how do you know the parity of particles to know whether they act through weak force? Is there a grouping ...
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0answers
32 views

Regge trajectories for higher spins

I have read that Regge theory did/does predict higher spin meson states, but that at higher spins the data becomes fuzzy for spins greater than 4. Why is this so? In the book "A Brief History of ...
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0answers
51 views

Interpretation of vector mesons in QCD

It is well-known that scalar mesons are interpreted as pseudogoldstone bosons which is connected with spontaneous broken $SU(3) \times SU(3)$ symmetry to $SU(3) \times SU(3) / SU(3)_{chiral}$. Is ...
3
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2answers
158 views

$\mathrm{\rho^0}$ meson decay via the weak interaction?

Of course, the $\mathrm{\rho^0}$ meson can decay in $\mathrm{\pi^{+}\ \pi^{-}}$ through the strong interaction. Using Feynman diagrams, I cannot understand why the same decay couldn't happen through ...
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0answers
25 views

How to calculate D0->K+K- decay with QCD factorization?

I am studying the decay of D0->K+K- and I calculated the result of Branching Ratio by Naive QCD and I wrote all the equations for amplitude and branching Ration and Hamiltonian and... for this decay ...
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1answer
81 views

Why is rho to two pions not allowed? [duplicate]

Why is the $\rho^0 \rightarrow \pi^0 + \pi^0$ decay not allowed? I have seen this question but I am not satisfied with the answers. The $J^{PC}$ of the $\rho$ and $\pi$ are $1^{--}$ and $0^{-+}$ ...
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0answers
97 views

Is $\overline{B}^0$ really the antiparticle of $B^0$?

They have a different mass, which is apparently forbidden by $CPT$ symmetry. Does this have anything to do with them having two distinct energy eigenstates?
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1answer
88 views

Why is the mass of a particle different from its antiparticle?

Like, for example, the neutrinos and the $B_0$ and the $\overline{B}^0$ mesons?
5
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1answer
397 views

How can mesons have spin greater than 1?

My understanding was that a meson, being made of a quark and an antiquark (spin 1/2) could only have spin 1 or 0, by addition of angular momentum states. I just saw an article ...
2
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1answer
31 views

$B^{0}$ decay into $K^{+}$ and $K^{-}$: equally probable?

One of the decay modes of the $B^0$ meson is $B^0 \rightarrow K^{*0} \mu^{+}\mu^{-}$, with $K^{*0} \rightarrow K^+ \pi^-$. But because of the $B$-meson oscillatios, we can also have $ B^0 ...
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1answer
104 views

Semileptonic decays of the $B_c$ meson

I am struggling with calculating the exclusive semileptonic $B_c^+\rightarrow J/\psi l^+\nu_l$ decay. I learnt that the amplitude is given by a product of the leptonic current $L^{\mu}$ and the ...
8
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2answers
461 views

How do we measure meson decay constants?

I'm trying to understand how people actually measure decay constants that are discussed in meson decays. As a concrete example lets consider the pion decay constant. The amplitude for $\pi ^-$ decay ...
1
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1answer
168 views

What is the leading order Feynman diagram for nucleon-anti-nucleon annihilation into two mesons ($\psi^{\dagger} \psi \to \phi\phi$)?

I am working with a standard basic scalar Yukawa theory. I.e. the only interaction term is $-g\psi^\dagger\psi\phi$, where the $\phi$ field quanta are the mesons, the $\psi$ field quanta are the ...
2
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2answers
80 views

Kaon reaction rates

I have a big difficulty in grasping weak interactions. For example, how would I go on about determining the following: $\frac{\Gamma(K^{+} \to \pi^{+}K^{0})}{\Gamma(K^{+} \to \pi^{0}K^{+})}$ I ...
4
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1answer
76 views

String breaking in QCD

I have trouble understanding string breaking in QCD. I have read an article on arxiv (http://arxiv.org/abs/hep-lat/0505012), and I still don't understand what truly happens. My understanding of ...
2
votes
3answers
544 views

What is the difference between a charged rho meson and a charged pion?

They both seem to have the same quark content: $$\rho^{+} = u\bar{d} = \pi^{+}$$ and $$\rho^{-} = \bar{u}d = \pi^{-}$$ What is different about the two?
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0answers
97 views

Probability of forming mesons vs baryons

When a heavy quark hadronizes it has some probability of forming a meson vs forming a baryon. I suspect there is a well known branching ratio for each type of hadron. Does anyone know what the ...
7
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3answers
1k views

Why is the decay of a neutral rho meson into two neutral pions forbidden?

Why is the decay of a neutral rho meson into two neutral pions forbidden? (Other modes of decay are possible though.) Is it something with conservation of isospin symmetry or something else? Please ...
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0answers
118 views

Is Veneziano amplitude able to explain the physical properties of strongly interacting hadrons (such as proton and neutron)? [duplicate]

In theoretical physics, the Veneziano amplitude refers to the discovery made in 1968 by Italian theoretical physicist Gabriele Veneziano that the Euler beta function, when interpreted as a scattering ...
8
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1answer
103 views

B-meson naming convention

An unbarred $B$-meson contains $\bar{b}$ (an anti-bottom quark), whereas a barred $\bar{B}$-meson contains $b$ (a bottom quark). What is the historical reason for this hellish naming convention?
2
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1answer
276 views

Feynman diagram for $\overline{K}\,\!^0$ antimeson production on the quark-level

I've recently stumbled upon a physics problem concerning $\overline{K}\,\!^0$ antimeson production. In this particular example, colliding a $\pi^-$ meson with a stationary proton yields a $K^0$ meson ...
7
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2answers
302 views

Quantum field theory meson scattering calculation (scalar yukawa theory)

Please see this question for a clear background of the notation I use. My issue is that I want to use Wick's theorem to calculate the amplitude of meson ...
5
votes
1answer
295 views

Does the color of a quark matter in a meson?

QCD and confinement specify that hadrons must be color-neutral. My understanding is that this means you can have mesons (quark + antiquark) or baryons with 3 quarks, one of each color: ...
3
votes
1answer
195 views

Is there a tb meson?

I was wandering around the particle date group page for meson and couldn't find a meson for top-bottom, which from symmetry you would expect. Q1: Is this because it hasn't been found? Q2: There is ...
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3answers
3k views

What does it mean that the neutral pion is a mixture of quarks?

The quark composition of the neutral pion ($\pi^0$) is $\frac{u\bar{u} - d\bar{d}}{\sqrt{2}}$. What does this actually mean? I think it's bizarre that a particle doesn't have a definite composition. ...