Scaling of the B and D meson spectrum in lattice QCD

We give results for the $B$ and the $D$ meson spectrum using NRQCD on the lattice in the quenched approximation. The masses of radially and orbitally excited states are calculated as well as $S$-wave hyperfine and $P$-wave fine structure. Radially excited $P$-states are observed for the first time. Radial and orbital excitation energies match well to experiment, as does the strange-non-strange $S$-wave splitting. We compare the light and heavy quark mass dependence of various splittings to experiment. Our $B$-results cover a range in lattice spacings of more than a factor of two. Our $D$-results are from a single lattice spacing and we compare them to numbers in the literature from finer lattices using other methods. We see no significant dependence of physical results on the lattice spacing. PACS: 11.15.Ha 12.38.Gc 14.40.Lb 14.40.NdComment: 78 pages, 29 tables, 30 figures Revised version. Minor corrections to spelling and wordin

GW250114: Testing Hawking’s area law and the Kerr nature of black holes

The gravitational-wave signal GW250114 was observed by the two LIGO detectors with a network matched-filter signal-to-noise ratio of 80. The signal was emitted by the coalescence of two black holes with near-equal masses m1 ¼ 33.6þ1.2 −0.8M⊙ and m2 ¼ 32.2þ0.8 −1.3M⊙, and small spins χ1;2 ≤ 0.26 (90% credibility) and negligible eccentricity e ≤ 0.03. Postmerger data excluding the peak region are consistent with the dominant quadrupolar ðl ¼ jmj ¼ 2Þ mode of a Kerr black hole and its first overtone. We constrain the modes’ frequencies to 30% of the Kerr spectrum, providing a test of the remnant’s Kerr nature. We also examine Hawking’s area law, also known as the second law of black hole mechanics, which states that the total area of the black hole event horizons cannot decrease with time. A range of analyses that exclude up to five of the strongest merger cycles confirm that the remnant area is larger than the sum of the initial areas to high credibility

GW241011 and GW241110: exploring binary formation and fundamental physics with asymmetric, high-spin black hole coalescences

We report the observation of gravitational waves from two binary black hole coalescences during the fourth observing run of the LIGO–Virgo–KAGRA detector network, GW241011 and GW241110. The sources of these two signals are characterized by rapid and precisely measured primary spins, nonnegligible spin–orbit misalignment, and unequal mass ratios between their constituent black holes. These properties are characteristic of binaries in which the more massive object was itself formed from a previous binary black hole merger and suggest that the sources of GW241011 and GW241110 may have formed in dense stellar environments in which repeated mergers can take place. As the third-loudest gravitational-wave event published to date, with a median network signal-to-noise ratio of 36.0, GW241011 furthermore yields stringent constraints on the Kerr nature of black holes, the multipolar structure of gravitational-wave generation, and the existence of ultralight bosons within the mass range 10−13–10−12 eV

GW231123: a binary black hole merger with total mass 190–265 M⊙

On 2023 November 23, the two LIGO observatories both detected GW231123, a gravitational-wave signal consistent with the merger of two black holes with masses 137+23-18 M⊙ and 101+22-50 M⊙ (90% credible intervals), at a luminosity distance of 0.7–4.1 Gpc, a redshift of 0.40+0.27-0.25, and with a network signal-to-noise ratio of ∼20.7. Both black holes exhibit high spins— 0.90+0.10-0.19 and 0.80+0.20-0.52, respectively. A massive black hole remnant is supported by an independent ringdown analysis. Some properties of GW231123 are subject to large systematic uncertainties, as indicated by differences in the inferred parameters between signal models. The primary black hole lies within or above the theorized mass gap where black holes between 60–130 M⊙ should be rare, due to pair-instability mechanisms, while the secondary spans the gap. The observation of GW231123 therefore suggests the formation of black holes from channels beyond standard stellar collapse and that intermediate-mass black holes of mass ∼200 M⊙ form through gravitational-wave-driven mergers

Methods for the aquarium maintenance of the common octopus of British waters, Eledone cirrhosa

Healthy, undamaged specimens survive well in recirculating aquarium seawater of about 36 parts per thousand salinity and pH 7.4, having 50mg 1 -1 nitrogen as nitrate, 500g bodyweight. Survival of healthy, wid-caught animals, commonly 4-6 months and up to 8 months, is apparently limited more by endogenous factors concerned with sexual maturation and lifespan than by aquarium conditions. Eggs have been laid but it has not yet been possible to hatch and rear them