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Holographic QCD and pion mass. Akitsugu Miwa (Institute of Physics, Univ of Tokyo, Komaba). based on JHEP 0706:020 [hep-th/0703024] with Koji.Hashimoto, Takayuki.Hirayama. 2. large # of D-branes ⇒ SUGRA solution. ( strong coupling picture ). Holographic QCD.
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Holographic QCD and pion mass Akitsugu Miwa (Institute of Physics, Univ of Tokyo, Komaba) based on JHEP 0706:020 [hep-th/0703024] with Koji.Hashimoto, Takayuki.Hirayama
2. large # of D-branes ⇒ SUGRA solution ( strong coupling picture ) Holographic QCD Holographic QCD approach: String/Gauge duality⇒strong coupling QCD steps in the Holographic QCD: 1. D-branes in flat spacetime ( weak coupling picture ) open string fluctuation ⇒ QCD low energy “AdS/CFT conjecture” classical gravity on the near horizon region ⇒understanding of strong coupling QCD
4dim QCD S1 meson • separated D8/anti-D8 ⇒exact chiral symm. flat Sakai-Sugimoto model [Sakai, Sugimoto 04] weak coupling picture: strong coupling picture: •connected D8/anti-D8 ⇒ spontaneous chiral symm. breaking • massless pion near horizon
SS-model: = • connected D8/anti-D8 ⇒ only symm. • massive quarks (expectation) deformation of SS-model (weak coupling picture) [Callan,Maldacena (98)] [Constable,Myers,Tafjord (01)] deformation: = S4 instanton ( from R4 instanton ): ⇒
• -integral: mode expansion, diagonalize c.f.) in the SS-model: pion vector meson strong coupling picture 1: meson spectrum open string fluctuation: KK-reduction: ( x , U , S4 ) ⇒ ( x ) • S4-integral: only the lowest modes meson spectrum:
pion mass term • identify and in our model • rewrite the D-brane action using pion mass term strong coupling picture 2: chiral perturbation low energy effective Lagrangian of QCD: chiral perturbation from D-brane model: corresponding deformation of QCD: ⇔
meson spectrum:• non-zero pion mass • no effect on vector meson spectrum chiral perturbation: • no quark mass term : thin throat Summary and Discussion motivation: deformation of SS-model: connect D8/anti-D8 in flat spacetime⇒ explicitly broken chiral symm. separate D8 from D4⇒quark mass (expectation) results: discussion: why no quark mass term ?