Related Experiment Video
Updated: Jul 10, 2026
07:46
Setting Limits on Supersymmetry Using Simplified Models
Published on: November 15, 2013
Properties of L=1 B(1) and B(2)* mesons
V M Abazov1, B Abbott, M Abolins
1Joint Institute for Nuclear Research, Dubna, Russia.
Physical Review Letters
|November 13, 2007
Summary
Researchers provide the first strong evidence distinguishing excited B mesons, B(1) and B(2)*, as separate states. Their masses and production rates were precisely measured in decays to B(+)pi(-), offering new insights into heavy meson spectroscopy.
Area of Science:
- Particle Physics
- High Energy Physics
- Quantum Chromodynamics
Background:
- The study of heavy mesons is crucial for understanding the strong nuclear force.
- Excited states of B mesons provide sensitive probes of QCD dynamics.
- Previous experimental data lacked the resolution to definitively separate B(1) and B(2)* states.
Purpose of the Study:
- To present the first strong evidence for the resolution of excited B mesons B(1) and B(2)* as distinct states.
- To precisely measure the masses of the B(1) and B(2)* mesons.
- To determine the relative production rate of these excited B mesons.
Main Methods:
- Analysis of fully reconstructed decays of B mesons.
- High-precision mass measurements using invariant mass reconstruction.
- Statistical analysis to determine significance and production fractions.
Main Results:
- Strong evidence for the separation of B(1) and B(2)* resonances is presented.
- The mass of B(1) is measured as 5720.6 ± 2.4 ± 1.4 MeV/c².
- The mass difference ΔM between B(2)* and B(1) is 26.2 ± 3.1 ± 0.9 MeV/c², yielding a B(2)* mass of 5746.8 ± 2.4 ± 1.7 MeV/c².
- The production rate of B(1) and B(2)* mesons is (13.9 ± 1.9 ± 3.2)% of the B+ meson production rate.
Conclusions:
- This work resolves the long-standing ambiguity in the B(1) and B(2)* meson masses.
- The precise measurements contribute significantly to the field of heavy meson spectroscopy.
- The findings offer valuable data for theoretical models of excited hadron states.
Related Concept Videos
01:24π Molecular Orbitals of 1,3-Butadiene
Conjugated dienes have lower heats of hydrogenation than cumulated and isolated dienes, making them more stable. The enhanced stabilization of conjugated systems can be understood from their π molecular orbitals.
The simplest conjugated diene is 1,3-butadiene: a four-carbon system where each carbon is sp2-hybridized and has an unhybridized p orbital that contains an unpaired electron. According to molecular orbital theory, atomic orbitals combine to form molecular orbitals such that the number...
The simplest conjugated diene is 1,3-butadiene: a four-carbon system where each carbon is sp2-hybridized and has an unhybridized p orbital that contains an unpaired electron. According to molecular orbital theory, atomic orbitals combine to form molecular orbitals such that the number...
02:32The de Broglie Wavelength
In the macroscopic world, objects that are large enough to be seen by the naked eye follow the rules of classical physics. A billiard ball moving on a table will behave like a particle; it will continue traveling in a straight line unless it collides with another ball, or it is acted on by some other force, such as friction. The ball has a well-defined position and velocity or well-defined momentum, p = mv, which is defined by mass m and velocity v at any given moment. This is the typical...
01:08Spin–Spin Coupling Constant: Overview
In bromoethane, the three methyl protons are coupled to the two methylene protons that are three bonds away. In accordance with the n+1 rule, the signal from the methyl protons is split into three peaks with 1:2:1 relative intensities. The methylene protons appear as a quartet, with the relative intensities of 1:3:3:1.
Qualitatively, any spin plus-half nucleus polarizes the spins of its electrons to the minus-half state. Consequently, the paired electron in the hydrogen–carbon bond must have a...
Qualitatively, any spin plus-half nucleus polarizes the spins of its electrons to the minus-half state. Consequently, the paired electron in the hydrogen–carbon bond must have a...
01:18Structure of Benzene: Molecular Orbital Model
According to the molecular orbital (MO) model, benzene has a planar structure with a regular hexagon of six sp2 hybridized carbons. As shown in Figure 1, each carbon is bonded to three other atoms with C–C–C and H–C–C bond angles of 120°. The C–H bond length is 109 pm, and the C–C bond length is 139 pm which is midway between the single bond length of sp3 hybridized carbons (154 pm) and sp2 hybridized carbons (133 pm).
02:43Quantum Numbers
It is said that the energy of an electron in an atom is quantized; that is, it can be equal only to certain specific values and can jump from one energy level to another but not transition smoothly or stay between these levels.
01:13¹H NMR: Complex Splitting
A proton M that is coupled to a proton X results in doublet signals for M. However, NMR-active nuclei can be simultaneously coupled to more than one nonequivalent nucleus. When M is coupled to a second proton A, such as in styrene oxide, each peak in the doublet is split into another doublet.
Splitting diagrams or splitting tree diagrams are routinely used to depict such complex couplings. While drawing splitting diagrams, the splitting with the larger coupling constant is usually applied first.
Splitting diagrams or splitting tree diagrams are routinely used to depict such complex couplings. While drawing splitting diagrams, the splitting with the larger coupling constant is usually applied first.