Can Chiral Symmetry Explain the Small Pentaquark Width?

It is shown that the decay amplitude for the Jaffe-Wilczek type pentaquarks is not suppressed by chiral symmetry. On the other hand, pentaquarks of positive or negative parity built up of an antiquark and two chirally different diquarks in an $S$-state are stable in the limit of a strictly unbroken chiral symmetry. These states can decay only via the spontaneous breaking of chiral symmetry. However, this breaking is strong because of the sizeable magnitude of the quark condensate. Thus, chiral symmetry cannot be the cause of a tiny decay amplitude, even for pentaquarks which are stable in the strict chiral symmetry limit.Comment: Talk given at the 10th International Baryons Conference at Ecole Polytechnique (Palaiseau, France) 25 - 29 October 200

Pentaquarks in the Chiral Symmetry Limit

We demonstrate that a five quark state of positive parity with an internal P-wave structure - usually pictured as a composite of an antiquark and two diquarks in a P-wave state - can couple to nucleons and Goldstone particles in a chirally invariant way. The corresponding decay width is generally not suppressed. A pentaquark of positive or negative parity with an internal S-wave structure, which may be viewed as a composite of an antiquark and two chirally different diquarks in an S-state, does not couple to nucleons and light mesons in the limit of an unbroken chiral symmetry. It is stable in this limit. However, such states can decay via the effect of the spontaneous breaking of chiral symmetry. This breaking is strong because of the sizeable magnitude of the quark condensate. Thus, chiral symmetry cannot be the cause of a tiny decay amplitude, even for pentaquarks stable in a strict chiral symmetry limit.Comment: Modified version. We added a discussion of the effect of spontaneous breaking of chiral symmetry on the pentaquark. This has changed part of our conclusions: we argue that the effect is large indicating that chiral symmetry cannot be the origin of the small width of the pentaquar

Acceptability Judgements via Examining the Topology of Attention Maps

The role of the attention mechanism in encoding linguistic knowledge has received special interest in NLP. However, the ability of the attention heads to judge the grammatical acceptability of a sentence has been underexplored. This paper approaches the paradigm of acceptability judgments with topological data analysis (TDA), showing that the geometric properties of the attention graph can be efficiently exploited for two standard practices in linguistics: binary judgments and linguistic minimal pairs. Topological features enhance the BERT-based acceptability classifier scores by $8$%-$24$% on CoLA in three languages (English, Italian, and Swedish). By revealing the topological discrepancy between attention maps of minimal pairs, we achieve the human-level performance on the BLiMP benchmark, outperforming nine statistical and Transformer LM baselines. At the same time, TDA provides the foundation for analyzing the linguistic functions of attention heads and interpreting the correspondence between the graph features and grammatical phenomena.Comment: Accepted to EMNLP 2022 Finding

Potential energy and dipole moment surfaces of HCO- for the search of H- in the interstellar medium

Potential energy and permanent dipole moment surfaces of the electronic ground state of formyl negative ion HCO- are determined for a large number of geometries using the coupled-cluster theory with single and double and perturbative treatment of triple excitations ab initio method with a large basis set. The obtained data are used to construct interpolated surfaces, which are extended analytically to the region of large separations between CO and H- with the multipole expansion approach. We have calculated the energy of the lowest rovibrational levels of HCO- that should guide the spectroscopic characterization of HCO- in laboratory experiments. The study can also help to detect HCO- in the cold and dense regions of the interstellar medium where the anion could be formed through the association of abundant CO with still unobserved H-

Advice on fishing opportunities for Greenland halibut in 2024 in ICES subareas 1 and 2

Stock Name: Northeast Arctic Greenland halibut (ICES areas 1 and 2) The Joint Russian-Norwegian Arctic Fisheries Working Group (JRN-AFWG) advises that when the MSY approach is applied, catches in 2024 should be no more than 15 560 tonnes.publishedVersio

Advice on fishing opportunities for Northeast arctic haddock in 2024 in ICES subareas 1 and 2

Stock Name: Northeast Arctic haddock (ICES areas 1 and 2) The Joint Russian-Norwegian Arctic Fisheries Working Group (JRN-AFWG) advises that when the Joint Norwegian–Russian Fisheries Commission management plan is applied, catches in 2024 should be no more than 127 550 tonnes.publishedVersio

Advice on fishing opportunities for Northeast Arctic cod in 2024 in ICES subareas 1 and 2

Stock Name: Northeast Arctic cod (ICES areas 1 and 2) The Joint Russian-Norwegian Arctic Fisheries Working Group (JRN-AFWG) advises that when the Joint Norwegian–Russian Fisheries Commission management plan is applied, catches in 2024 should be no more than 453 427 tonnes.publishedVersio

Report of the Joint Russian-Norwegian Working Group on Arctic Fisheries (JRN-AFWG) 2023

On 30 th March 2022 all Russian participation in ICES was temporally suspended. Although the announcement of the suspension stressed the role of ICES as a “multilateral science organization”, this suspension applied not only to research activities, but also to the ICES work providing fisheries advice for the sustainable management of fish stocks and ecosystems. As a result of the suspension, the ICES AFWG provided advice only for saithe, coastal cod north, coastal cod south, and golden redfish ( Sebastes norvegicus ). Northeast Arctic (NEA) cod, haddock and Greenland halibut assessments have been conducted outside of ICES in a newly constituted Joint Russian-Norwegian Working Group on Arctic Fisheries (JRN-AFWG). Although this work has been conducted independently of ICES, the methodologies agreed at ICES benchmarks and agreed HCRs (Harvest Control Rules) have been followed in providing this advice. The Greenland halibut model has been revised at an ICES benchmark in 2023. The JRN-AFWG has agreed to use the new ICES model, with the addition of revising the Russian survey tuning index (as was recommended at the benchmark). Although the overall biomass level in the model has been revised, the trends and advice are similar to the old model. The Greenland halibut advice is for one year to bring the timing back in line with the slope survey, after this a two-year advice cycle will resume. The main worry with that stock is a history of TACs and catches well above advice. Given that the model is now indicating that the stock will drop below B pa by the end of 2023, continuing to set quota above advice poses a risk of serious harm to the stock.publishedVersio

Collins and Sivers asymmetries in muonproduction of pions and kaons off transversely polarised protons

Measurements of the Collins and Sivers asymmetries for charged pions and charged and neutral kaons produced in semi-inclusive deep-inelastic scattering of high energy muons off transversely polarised protons are presented. The results were obtained using all the available COMPASS proton data, which were taken in the years 2007 and 2010. The Collins asymmetries exhibit in the valence region a non-zero signal for pions and there are hints of non-zero signal also for kaons. The Sivers asymmetries are found to be positive for positive pions and kaons and compatible with zero otherwise. © 2015