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Wednesday, January 11, 2012

New Heavy Exotic Hadrons

Figure 1. Existing standard hadrons and exotic hadrons. At the B Factory experiment, a series of new exotic mesons containing charm quarks (c) have been discovered. Unlike these exotic mesons, the newly discovered Zb particles contain bottom quarks (b) and have an electric charge. If only one bottom quark and one anti-bottom quark ( b ) are contained, the resulting particle is electrically neutral. Thus, the Zb must also contain at least two more quarks (e.g., one up quark (u) and one anti-down quark ( d )). Credit: PhysOrg

( -- Two unexpected new hadrons containing bottom quarks have been discovered by the Belle Experiment using the High Energy Accelerator Research Organization (KEK)'s B Factory (KEKB), a highly-luminous, electron-positron collider. These new particles have electric charge and are thought to be "exotic" hadrons -- non-standard hadrons, containing at least four quarks. Previously, a series of new and unexpected exotic hadrons containing charm and anti-charm quarks have been observed. This latest discovery from Belle demonstrates the existence of exotic hadrons containing at least four quarks in a particle system including bottom quarks .
in PhysOrg (follow the link to read entire article)

The Belle experiment conducts collisions between electrons and positrons.

Highlights of the Belle experiment so far include
  • the first observation of CP-violation outside of the kaon system (2001)
  • observation of: B \to K^* l^+ l^- and b \to s l^+ l^-
  • measurement of ϕ3 using the B \to D K, D \to K_S \pi^+ \pi^- Dalitz plot
  • measurement of the CKM quark mixing matrix elements Vub | and Vcb |
  • observation of direct CP-violation in B^0 \to \pi^+ \pi^- and B^0 \to K^- \pi^+
  • observation of b \to d transitions
  • evidence for B \to \tau \nu
  • observations of a number of new particles including the X(3872)

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