| Newsletter Italian August/September 2018 |
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ICRANet Newsletter
ICRANet Newsletter
Agosto - Settembre 2018
INDICE
1. The event GRB 170817A-GW170817-AT 2017gfo as WD-WD merger 2. Predizione e conferma del GRB 180728A / SN 2018fip da parte degli scienziati ICRANet 3. La Notte dei ricercatori all'ICRANet, Pescara, 28 Settembre 2018 4. Visita del Professor Ruffini alla Tsinghua University (Pechino) e al TD Lee Institute (Shanghai), 8 -15 Agosto 2018 5. Visita e seminario del Professor Ruffini al LAPP, Annecy, 3 - 4 Settembre 2018 6. Visita del Professor Ruffini in Kazakhstan e 3 nuovi Accordi di Collaborazione, 6 - 8 Settembre 2018 7. Visite scientifiche all'ICRANet 8. Edizione speciale della rivista "Science and Innovation" in Bielorussia 9. Pubblicazioni recenti
1. The event GRB 170817A-GW170817-AT 2017gfo as WD-WD merger
The paper "GRB 170817A-GW170817-AT 2017gfo and the observations of NS-NS, NS-WD and WD-WD mergers" by J. A. Rueda, R. Ruffini, Y. Wang, Y. Aimuratova; U. Barres de Almeida, C. L. Bianco, Y. C. Chen, R. V. Lobato, C. Maia, D. Primorac, R. Moradia, and J. F. Rodriguez, is published in JCAP 10 (2018) 006 on October 3, 2018.
The LIGO-Virgo Collaboration has announced the detection of GW170817 and has associated it with the gamma-ray bursts (GRB) 170817A. These signals have been followed after 11 hours by the optical and infrared kilonova emission of AT 2017gfo. The origin of this complex phenomenon has been attributed to a neutron star-neutron star (NS-NS) binary merger. The kilonova in this case would be powered by the radioactive decay of r-process heavy material synthesized in the NS-NS merger. However, as we show in this work, the gamma- and X-rays emissions of GRB 170817A are in clear contrast with the ones of any short-duration GRB associated either with a NS-NS merger or with other merger types (see details below). In fact, in order to probe the GW-GRB-kilonova association we confront our current understanding of the gravitational waves and associated electromagnetic radiation with four observed GRBs originating in binaries with NS and white dwarf (WD) components: 1) GRB 090510 the prototype of the authentic short GRB (S-GRB) subclass produced by a NS-NS merger leading to a black hole (BH); 2) GRB 130603B the prototype of the short gamma-ray flash (S-GRF) subclass produced by a NS-NS merger leading to massive NS (MNS); 3) GRB 060614 the prototype of the GRF subclass produced by a NS-WD merger leading to a MNS; and 4) we propose GRB 170817A as the prototype of a new subclass of GRB by a WD-WD merger leading to massive WD, and an AT 2017gfo-like kilonova. None of them support the triptych GW-GRB-kilonova. 
There are a number of new astrophysical results: a. The NS-NS scenario cannot explain GRB170817A-GW170817 since this solution implies an X and gamma-ray prompt emission missing in GRB 170817A (see data up to 10 s data in the figure). b. Instead, X- and gamma-ray observations of GRB 170817A have led us to propose a new subclass of GRBs originating from WD-WD mergers leading to a massive WD. The occurrence rate of these mergers can explain the rate of GRB 170817A-like sources, they produce a gamma- and X-ray emission consistent with GRB 170817A and cannot be associated with GW170817. c. The kilonova AT 2017gfo can be powered by a different physical mechanism that the radioactive decay of r-processed heavy nuclei in the ejecta of NS-NS mergers: the cooling of the ejecta expelled in a WD-WD merger and heated up by fallback accretion onto the newly-formed massive WD. d. The WD-WD merger ejecta have a lighter nuclear composition with respect to the r-processed heavy nuclei present in the ejecta of a NS-NS merger. The identification of atomic species in kilonova spectra can therefore discriminate between the two scenarios. However, such an identification has not been possible in observed kilonovae since it needs accurate models of atomic spectra, nuclear reaction network, density profile, as well as radiative transport (opacity), not yet available in the literature. e. The outcome configuration of a GRB from WD-WD merger, namely a massive, highly magnetized, fast rotating WD, can become observable as a soft gamma repeater (SGR) or anomalous X-ray pulsar (AXP) as indicated in the WD-pulsar model introduced by Malheiro, Rueda and Ruffini in 2012. f. The association of GRB 170817A and GW170817, from an observational point of view is, in our opinion, not yet sufficiently established to formulate a well-motivated answer on the non-null chance coincidence probability of the events. It is thus auspicable that the LIGO collaboration releases the templates of GW170817 in the interferometers to reconstruct the precise chronology of the space-time sequence of events in the LIGO detectors and in the Fermi and Integral satellites, necessary to validate the GW170817-GRB 170817A association. JCAP website: http://iopscience.iop.org/article/10.1088/1475-7516/2018/10/006 arXiv: https://arxiv.org/abs/1802.10027
2. Predizione e conferma del GRB 180728A / SN 2018fip da parte degli scienziati ICRANet
After having successfully predicted the SN 2013cq associated with GRB 130427A (Ruffini et al.2013), as an example for the BdHN case, on 28 July 2018, ICRANet researchers led by prof. Remo Ruffini had the opportunity to predict of the supernova (SN) appearance in an X-ray flash (XRF) case.
At 17:29:00 UT, on 28 July 2018, the Swift-BAT triggered and located GRB 180728A. The BAT light curve shows a small precursor followed ∼ 10 s later by a bright pulse of ∼ 20 s duration (Starling2018). Swift-XRT did not slew immediately due to the Earth limb constraint, it began observing the field 1730.8 s after the BAT trigger (Perri2018). The Fermi-GBM triggered and located GRB 180728A at 17:29:02.28 UT. The angle from the Fermi-LAT boresight at the GBM trigger time is 35 degrees. The GBM light curve consists of a precursor and a very bright peak with a duration (T90) of about 6.4 s (50-300 keV) (Veres2018). A red continuum is detected across the spectral range of VLT/X-shooter, the absorption features due to Mg II (3124, 3132), Mg I (3187), and Ca II (4395, 4434) at a consistent redshift of z = 0.117. Although Galactic extinction in this direction is significant, a cam- paign to study the anticipated associated supernova should still be practical with moderate-aperture telescopes at this redshift (Rossi2018). With the above first 3 days observations after the trigger of the GRB, the group has predicted that a supernova would appear in 14.7 ± 2.9 days (Ruffini2018), quoted here: GCN 23066: GRB 180728A: A long GRB of the X-ray flash (XRF) sub- class, expecting supernova appearance Link: https://gcn.gsfc.nasa.gov/gcn3/23066.gcn3 GRB 180728A has T90 = 6.4 s (Rossi2018), peak energy 142(-15, +20) keV, and isotropic energy Eiso = (2.33 ± 0.10) × 1051 erg (Frederiks2018). It presents the typical characteristic of a subclass of long GRBs called X-ray flashes (XRFs, seeRuffini et al.2016), originat- ing from a tight binary of a COcore undergoing a supernova explosion in presence of a companion neutron star (NS) that hypercritically accretes part of the supernova matter. The outcome is a new binary composed by a more massive NS (MNS) and a newly born NS (vNS). Using the averaged observed value of the optical peak time of supernova (Cano et al.2017) and considering the redshift z = 0.117 (Rossi2018), a bright optical signal will peak at 14.7 ± 2.9 days after the trigger (12 August 2018, uncertainty from August 9th to August 15th) at the location of RA=253.56472 and DEC=-54.04451, with an uncertainty 0.43 arcsec (LaPorte2018). The follow-up observations, especially the optical bands for the SN, as well as attention to binary NS pulsar behaviours in the X-ray afterglow emission, are recommended. On 18 July 2018, Izzo (2018) reported the discovery of the supernova appearance: GCN 23142: GRB 180728A: discovery of the associated supernova Link: https://gcn.gsfc.nasa.gov/gcn3/23142.gcn3 ... Up to now, we have observed at three epochs, specifically at 6.27, 9.32 and 12.28 days after the GRB trigger. The optical counterpart is visible in all epochs using the X-shooter acquisition camera in the g, r and z filters. We report a rebrightening of 0.5 ± 0.1 mag in the r band between 6.27 and 12.28 days. This is consistent with what is observed in many other low-redshift GRBs, which in those cases is indicative of an emerging type Ic SN ... For the last spectrum, we attempted the identification of a few features. In particular, we identify the broad dip at 7600 AA as due to the blend O I 8446 AA and Ca II 8492 AA, at the expansion velocity of 30,000 km s-1. At this velocity, we also identify the Si II 6355 doublet, as well as C II 6580. The width of the lines spans several thousand km s-1. Independent of the interpretation of the lines, the overall shape of the continuum, together with the presence of several absorption features a few thousands km s-1 wide, strongly indicate that this is a SN. The lack of identified H and He in the spectra suggests a classification of type Ic ... and the SN was confirmed in Selsing (2018). This SN associated with GRB 180728A is named SN 2018fip by the Transient Name Server. Therefore the prediction was confirmed.
3. La Notte dei ricercatori all'ICRANet,Pescara, 28 Settembre 2018
L'evento si è svolto Venerdì 28 Settembre presso il centro ICRANet a Pescara, alla presenza del prefetto della città Gerardina Basilicata e di numerosi studenti e cittadini. Dopo i saluti di benvenuto del Professor Remo Ruffini, Direttore ICRANet, si sono susseguiti diversi interventi da parte di ricercatori e studenti di Dottorato ICRANet (Dr Wang Yu, Yerlan Aimuratov e Dr Luca Izzo) che hanno illustrato il GRB 180727A e la supernova del 15 agosto 2018, da parte del Prof. Costantino Sigismondi (ITIS Galileo Ferraris – Roma) sui cinquant'anni dell'uomo sulla Luna, e da parte del Professor Ruffini e della Faculty ICRANet, che hanno aperto il dibattito con i partecipanti sulle recenti e future prospettive della scienza. 
Foto di gruppo con alcuni dei partecipanti alla "Notte dei Ricercatori all'ICRANet" il 28 Settembre. Gli interventi sono stati accompagnati da proiezioni video in tutta la struttura, del "Caso Neutrino", de "l'Assoluto Relativo", e delle conferenze tenutesi presso la Fondazione Marco Besso a Roma nel quadro del progetto finanziato dal Ministero Italiano dell'Educazione, Università e Ricerca (MIUR) "Del Talento e della curiosità. Quando l'aquila e il passero volano insieme". Inoltre, i partecipanti hanno anche avuto l'occasione di visitare le mostra organizzata dall'ICRANet dedicata alla nascita dell'Astrofisica Relativistica ed ai suoi maggiori rappresentanti, quali Einstein, Heisenberg e Fermi, così come la collaborazione scientifica tra ICRANet e la Cina, centrata sulla figura di Fang Li-Zhi, primo Presidente del Comitato Direttivo ICRANet. L'evento si è concluso con le osservazioni al telescopio di Saturno e Marte illustrate dagli studenti del Liceo Scientifico Galileo Galilei di Pescara, che hanno fornito spiegazioni sulle ottiche dei telescopi utilizzati. 
Studenti e cittadini ascoltano le spiegazioni dei Professori dell'ICRANet durante la Notte dei ricercatori all'ICRANet Il programma dell'evento può essere consultato al link: http://www.icranet.org/Notte_dei_ricercatori_2018/programma.pdf Per maggiori informazioni sull'evento: http://www.icranet.org/index.php?option=com_content&task=view&id=1210
4. Visita del Professor Ruffini alla Tsinghua University (Pechino) e al TD Lee Institute (Shanghai), 8 -15 Agosto 2018
Dall'8 al 15 Agosto 2018, il Professor Remo Ruffini, Direttore ICRANet, è volato in Cina su invito del Professore Shing-Tung Yau per tenere un seminario presso lo Yau Mathematical Sciences Center alla Tsinghua University di pechino, il 9 agosto 2018. Il seminario, dal titolo "On the observation of supernovae in the late phases of Gamma-Ray Bursts", ha presentato al pubblico i risultati ottenuti dal Professor Ruffini, dai ricercatori ICRANet e dagli studenti di dottorato (Y. Aimuratov, L. Becerra, C.L. Bianco, Y.C. Chen, D.M. Fuksman, M. Karlica, G. Mathews, R. Moradi, D. Primorac, J.A. Rueda, N. Sahakyan, Y. Wang, S.-S. Xue).
Per il video del seminario, si consulti il link: https://www.youtube.com/watch?v=Q6xssDI7a84
Accompagnato dal Dr Yu Wang, precedente studente di dottorato ICRANet, il Professor Ruffini ha inoltre visitato il Tsung-Dao Lee Institute di Shanghai, dove è stato invitato a tenere una C. C. Lin lecture sullo stesso tema presentato qualche giorno prima a Pechino. Durante questa visita, il Professor Ruffini ha anche avuto la possibilità di poter vedere e toccare il MG14 Award assegnato nel 2015 a T. D. Lee "for his work on white dwarfs motivating Enrico Fermi's return to astrophysics and guiding the basic understanding of neutron star matter and fields".
Per maggiori dettagli sul smeinario e sulla predizione delle 2 GCNs: http://www.icranet.org/documents/Abstract+2GCNs.pdf
5. Visita e seminario del Professor Ruffini al LAPP, Annecy, 3 - 4 Settembre 2018
Il 4 Settembre 2018, il Professor Remo Ruffini, Direttore ICRANet, ha visitato il LAPP (Laboratoire d'Annecy de Physique des Particules) ad Annecy, Francia, dove è stato invitato a tenere un seminario dal Direttore Giovanni Lamanna. Newl suo seminario, dal titolo "GRB180728A, our predicted Supernova denominated on 27 August SN2018fip and conceptual inferences" (https://indico.in2p3.fr/event/17864/), il Professor Ruffini ha illustrato il verificarsi di una sequenza di eventi a partire dal 28 Luglio, quando il GRB190728A è stato osservato dai satelliti SWIFT e Fermi. With his collaborators, they have identified this source as a member of the X-ray Flash (XRF) subclass of gamma-ray bursts (GRBs) in which a supernovae (SN) ejecta hypercritically accretes onto the neutron star (NS) companion leading to a more massive NS (MNS) and to a νNS-MNS binary. On the other hand, in the GCN23066 on 31 July 2018, they predicted the occurrence of a SN, indeed observed on 15 August (GCN23142). The significance of this result in discriminating the 8 different GRBs subclass has been analyzed.
6. Visita del Professor Ruffini in Kazakhstan e 3 nuovi Accordi di Collaborazione, 6 - 8 Settembre 2018
Dal 6 all'8 Settembre 2018, il Professor Remo Ruffini, Direttore ICRANet, si è recato in Kazakhstan per una visita ufficiale. Durante la prima giornata, il Professor Ruffini si è recato presso la Nazarbayev University ad Astana, dove ha tenuto il seminario "GRB180728A, our predicted Supernova denominated on 27 August SN2018fip and conceptual inferences" e dove ha incontrato il suo Vice Presidente per l'Innovazione e la Ricerca, Kanat Baigarin. Nella stessa giornata, ha incontrato anche S.E. Pasquale D'Avino, Ambasciatore d'Italia ad Astana, nella residenza dell'Ambasciata Italiana: il professor Ruffini ha avuto con lui una interessante discussione sulle numerose e potenziali possibilità di collaborazione tra l'Italia e il Kazakhstan nel campo della scienza. Durante la sua visita, il Professor Ruffini ha inoltre firmato un accordo di cooperazione con la L.N. Gumilyov Eurasian National University (ENU) di Astana con il suo Rettore, il Prof. Yerlan Battashevich Sydykov. Le principali attività congiunte previste nel quadro di questo accordo sono la promozione di attività teoriche e pratiche nel campo dell'astrofisica relativistica, scambi istituzionali di membri della faculty, ricercatori e studenti, l'implementazione degli sviluppi tecnologici e l'organizzazione di seminari, conferenze, workshops, corsi di training e ricerca e pubblicazioni congiunte. 
Il Professor Remo Ruffini, accompagnato dal Prof. Abishev Medeu, durante la cerimonia di firma del Memorandum of cooperation in science and education con il Center for Space Research & Technology (NCSR) ad Almaty. Il giorno seguente, il Professor Ruffini è volato ad Almaty, dove in mattinata, accompagnato dal Professor Abishev Medeu (Al-Farabi Kazakh National University) ha avuto un meeting con il Professor Chingis Omarov, Presidente del National Center for Space Research & Technology (NCSR). In questa occasione, l'ICRANet ha firmato un Memorandum of cooperation in science and education con la NCR nella persona del Professor Omarov (Presidente del centro). Il memorandum sarà valido per 5 anni a partire dalla data della sua firma. Le principali forme di cooperazione previste sono: lo scambio di expertise scientifica, attività di ricerca congiunte, partecipazione congiunta a bandi di ricerca e scambio di materiale e sapere scientifico. Dopo la cerimonia di firma, il Professor Ruffiniha visitato il Fesenkov Astrophysical Institute (FAPHI), avendo così l'opportunità di osservare il meteorite Sikhote-Alin, un meteorite di ferro caduto sulle Sikhote-Alin Mountains nel sud-est della Russia nel 1947. Sebbene cadute di grandi meteoriti di ferro fossero già state testimoniate e i frammenti già recuperati, mai prima di allora è caduto un meteorite così grande. In questo istituto, il Professor Ruffini ha inoltre tenuto il suo seminario "GRB180728A, our predicted Supernova denominated on 27 August SN2018fip and conceptual inferences".
Inoltre, il Professor Ruffini ha incontrato l'Accademico Tolegen Kozhamkulov, Presidente della Kazakh Physical Society (KPS) e, in questa occasione ha firmato l'accordo di cooperazione con l'ICRANet, rappresentata dal suo Direttore. Le principali attività congiunte previste nel quadro di questo accordo sono la promozione di attività teoriche e pratiche nel campo dell'astrofisica relativistica, scambi istituzionali di membri della faculty, ricercatori e studenti, l'implementazione degli sviluppi tecnologici e l'organizzazione di seminari, conferenze, workshops, corsi di training e ricerca e pubblicazioni congiunte. Nella giornata di sabato 8 Settembre, il Professor Ruffini, accompagnato dal Prof. Kozhamkulov, dal Prof. Abishev e dallo studente di dottorato Yerlan Aimuratov, ha incontrato S. E. Yerlan Sagadiyev, ministro dell'Educazione e della scienza del Kazakhstan presso il palazzo dell' Academy of Sciences ad Almaty. Il principale tema di discussione è stata la cooperazione del Kazakhstan con l'ICRANet.
Per il video del seminario del Professor Ruffini al Fesenkov Astrophysical Institute (FAPHI), Almaty, del 7 Settembre 2018: https://www.youtube.com/watch?v=f_w5-UZ1-sQ Per le press releases: http://www.kaznu.kz/en/3/news/one/14314/ https://www.inform.kz/ru/kazahstanskie-astrofiziki-sovmestno-s-ital-yancami-budut-izuchat-chernye-dyry_a3390191 (in russo) Per consultare i 3 accordi: • http://www.icranet.org/documents/AgreementICRANet-ENU.pdf (Accordo ICRANet - ENU) • http://www.icranet.org/index.php?option=com_content&task=view&id=1203 (Accordo ICRANet - KPS) • http://www.icranet.org/documents/AgreementICRANet-JSC-NCRS.pdf (MoU ICRANet - JSC NCRS)
7. Visite scientifiche all'ICRANet
8. Edizione speciale della rivista "Science and Innovation" in Bielorussia
* "Current state art in astrophysics and perspectives in Belarus" di Gregory Vereshchagin, ICRANet Faculty Professor; * "Cosmology and astrophysics today: dark energy and dark matter" di Ivan Siutsou and Yuri Vyblyi, ricercatori presso il centro ICRANet-Minsk; * "Gamma-ray bursts - the most bright and mysterious objects in the Universe" di Ivan Siutsou and Gregory Vereshchagin. Per maggiori informazioni (in russo) si può consultare il link: http://innosfera.by/content_2018_08
9. Pubblicazioni recenti
Bini D., Geralico A., Gravitational self-force corrections to tidal invariants for spinning particles on circular orbits in a Schwarzschild spacetime, to appear on Phys. Rev. D (2018), arXiv:1806.03495
Bini D., Geralico A., Gravitational self-force corrections to tidal invariants for particles on eccentric orbits in a Schwarzschild spacetime, published on Phys. Rev. D, Vol. 98, Iss. 6 - 15 September 2018, arXiv:1806.06635 We study tidal effects induced by a particle moving along a slightly eccentric equatorial orbit in a Schwarzschild spacetime within the gravitational self-force framework. We compute the first-order (conservative) corrections in the mass ratio to the eigenvalues of the electric-type and magnetic-type tidal tensors up to the second order in eccentricity and through the 9.5 post-Newtonian order. Previous results on circular orbits are thus generalized and recovered in a proper limit. Link: https://journals.aps.org/prd/abstract/10.1103/PhysRevD.98.064026 Bini D., Geralico A., Gravitational self-force corrections to tidal invariants for particles on circular orbits in a Kerr spacetime, published on Phys. Rev. D, Vol. 98, Iss. 6 - 15 September 2018, arXiv:1806.08765 We generalize to the Kerr spacetime existing self-force results on tidal invariants for particles moving along circular orbits around a Schwarzschild black hole. We obtain linear-in-mass-ratio (conservative) corrections to the quadratic and cubic electric-type invariants and the quadratic magnetic-type invariant in series of the rotation parameter up to the fourth order and through the ninth and eighth post-Newtonian orders, respectively. We then analytically compute the associated eigenvalues of both electric and magnetic tidal tensors. Link: https://journals.aps.org/prd/abstract/10.1103/PhysRevD.98.064040 Rosquist K., Bini D., Mashhoon B., Twisted Gravitational Waves of Petrov type D, published on Phys. Rev. D 98, 064039 (2018), Iss. 6 - 15 September 2018, arXiv:1807.09214 Twisted gravitational waves (TGWs) are nonplanar unidirectional Ricci-flat solutions of general relativity. Thus far only TGWs of Petrov type II are implicitly known that depend on a solution of a partial differential equation and have wave fronts with negative Gaussian curvature. A special Petrov type D class of such solutions that depends on an arbitrary function is explicitly studied in this paper and its Killing vectors are worked out. Moreover, we concentrate on two solutions of this class, namely, the Harrison solution and a simpler solution we call the w-metric and determine their Penrose plane-wave limits. The corresponding transition from a nonplanar TGW to a plane gravitational wave is elucidated. Link: https://journals.aps.org/prd/abstract/10.1103/PhysRevD.98.064039 N. Sahakyan, Lepto-hadronic γ-ray and neutrino emission from the jet of TXS 0506+056, Accepted for publication in ApJ on 16 Aug 2018, arXiv:1808.05651 The observation of IceCube-170922A event from the direction of TXS 0506+056 when it was in its enhanced γ-ray emission state offers a unique opportunity to investigate the lepto-hadronic processes in blazar jets. Here, the observed broadband emission of TXS 0506+056 is explained by boosted synchrotron/synchrotron self Compton emission from the jet whereas the γ-ray data observed during the neutrino emission- by inelastic interactions of the jet-accelerated protons in a dense gaseous target. The proton energy distribution is ∼E-2.50p, calculated straightforwardly from the data obtained by Fermi-LAT and MAGIC and if such distribution continues up to Ec,p=10 PeV, the expected neutrino rate is as high as ∼0.46 events during the long active phase of the source or ∼0.15 if the activity lasts 60 days. In this interpretation, the energy content of the protons above > GeV in blazar jets can be estimated as well: the required proton injection luminosity is ≅2.0×1048ergs-1 exceeding 103 times that of electrons ≅1045ergs-1 which are in equipartition with the magnetic field. As the required parameters are physically realistic, this can be an acceptable model for explanation of the neutrino and γ-ray emission from TXS 0506+056. Link: https://arxiv.org/abs/1808.05651 Hagen Kleinert and She-Sheng Xue, Composite fermions and their pair states in a strongly-coupled Fermi liquid, published in Nuclear Physics B936 (2018) 352-363 Our goal is to understand the phenomena arising in optical lattice fermions at low temperature in an exter-nal magnetic field. Varying the field, the attraction between any two fermions can be made arbitrarily strong, where composite bosons form via so-called Feshbach resonances. By setting up strong-coupling equations for fermions, we find that in spatial dimension d>2 they couple to bosons which dress up fermions and lead to new massive composite fermions. At low enough temperature, we obtain the critical temperature at which composite bosons undergo the Bose-Einstein condensate (BEC), leading to BEC-dressing massive fermions. These form tightly bound pair states which are new bosonic quasi-particles producing a BEC-type condensate. A quantum critical point is found and the formation of condensates of complex quasi-particles is speculated over. Link: https://doi.org/10.1016/j.nuclphysb.2018.09.023 |
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