Speaker:Dr.MitsutoshiFujita(SunYat-Sen))
Time: 3pm (Beijing Time), November 14th, 2022
Room:X2218
Title:Nucleon D-term in holographic QCD
Abstract:The D-term is one of the conserved charges of hadrons defined as the forward limit of the gravitational form factorD(t). We calculate the nucleon's D-term in a holographic QCD model in which the nucleon is described as a soliton in five dimensions. We show that the form factorD(t)is saturated by the exchanges of infinitely many0++and2++glueballs dual to transverse-traceless metric fluctuations on the Wick rotated AdS7black hole geometry. We refer to this phenomenon as `glueball dominance', in perfect analogy to the vector meson dominance of the electromagnetic form factors. However, the value at vanishing momentum transferD(t=0)can be interpreted as due to the exchange of pairs ofpionsand infinitely many vector and axial-vector mesons without any reference to glueballs. We find that the D-term is slightly negative as a result of a cancellation between theisovectorandisoscalarmeson contributions.
