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New results on the $^8$Be anomaly
/ Krasznahorkay, A J (Debrecen, Inst. Nucl. Res.) ; Csatlós, M (Debrecen, Inst. Nucl. Res.) ; Csige, L (Debrecen, Inst. Nucl. Res.) ; Gácsi, Z (Debrecen, Inst. Nucl. Res.) ; Gulyás, J (Debrecen, Inst. Nucl. Res.) ; Nagy, Á (Debrecen, Inst. Nucl. Res.) ; Sas, N (Debrecen, Inst. Nucl. Res.) ; Timár, J (Debrecen, Inst. Nucl. Res.) ; Tornyi, T G (Debrecen, Inst. Nucl. Res.) ; Vajda, I (Debrecen, Inst. Nucl. Res.) et al.
Recently, we observed anomalous internal pair creation for the M1 transition depopulating the 18.15 MeV isoscalar 1$^+$ state in $^8$Be. We observed a significant (σ = 7.37) peak-like deviation from the predicted angular correlation of the e+ e pairs at θ = 140°. [...]
2018 - 7 p.
- Published in : J. Phys.: Conf. Ser. 1056 (2018) 012028
Fulltext: pdf - PDF; 10.1088_1742-6596_1056_1_012028 - PDF;
In : Conference on Neutrino and Nuclear Physics, Catania, Italy, 15 - 21 Oct 2017
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2.
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New results on the Be-8 anomaly
/ Krasznahorkay, A J (Debrecen, Inst. Nucl. Res.) ; Csatlós, M (Debrecen, Inst. Nucl. Res.) ; Csige, L (Debrecen, Inst. Nucl. Res.) ; Gulyás, J (Debrecen, Inst. Nucl. Res.) ; Hunyadi, M (Debrecen, Inst. Nucl. Res.) ; Ketel, T J (NIKHEF, Amsterdam) ; Krasznahorkay, A (CERN) ; Kuti, I (Debrecen, Inst. Nucl. Res.) ; Nagy, Á (Debrecen, Inst. Nucl. Res.) ; Nyakó, B M (Debrecen, Inst. Nucl. Res.) et al.
Recently, we measured the e+e− angular correlations in internal pair creation (IPC) for the M1 transitions depopulating the 17.6 and 18.15 MeV states in 8Be, and observed a peak-like deviation from the predicted IPC for the 18.15 MeV transition, but not for the 17.6 MeV one. To the best of our knowledge no nuclear physics related description of such deviation can be made. [...]
SISSA, 2017 - 10 p.
- Published in : PoS BORMIO2017 (2017) 036
Fulltext: PDF; External link: PoS server
In : 55th International Winter Meeting on Nuclear Physics, Bormio, Italy, 23 - 27 Jan 2017, pp.036
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3.
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Confirmation of the existence of the X17 particle
/ Firak, D S (Debrecen U.) ; Krasznahorkay, A J (Debrecen, Inst. Nucl. Res.) ; Csatlós, M (Debrecen, Inst. Nucl. Res.) ; Csige, L (Debrecen, Inst. Nucl. Res.) ; Gulyás, J (Debrecen, Inst. Nucl. Res.) ; Koszta, M (Debrecen, Inst. Nucl. Res.) ; Szihalmi, B (Debrecen, Inst. Nucl. Res.) ; Timár, J (Debrecen, Inst. Nucl. Res.) ; Nagy, Á (Debrecen, Inst. Nucl. Res.) ; Sas, N J (Debrecen U.) et al.
In a 2016 paper, an anomaly in the internal pair creation on the $M1$ transition depopulating the 18.15 MeV isoscalar 1$^+$ state on $^8$Be was observed. This could be explained by the creation and subsequent decay of a new boson, with mass $m_Xc^2$ = 16.70 MeV. [...]
EPJ, 2020 - 5 p.
- Published in : EPJ Web Conf. 232 (2020) 04005
Published fulltext: PDF;
In : Heavy Ion Accelerator Symposium on Fundamental and Applied Science 2019, Canberra, Australia, 9 - 13 Sep 2019, pp.04005
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4.
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On the creation of the 17 MeV X boson in the 17.6 MeV M1 transition of $^8Be$
/ Krasznahorkay, A J (Debrecen, Inst. Nucl. Res.) ; Csatlós, M (Debrecen, Inst. Nucl. Res.) ; Csige, L (Debrecen, Inst. Nucl. Res.) ; Gulyás, J (Debrecen, Inst. Nucl. Res.) ; Ketel, T J (NIKHEF, Amsterdam) ; Krasznahorkay, A (CERN ; MIT) ; Kuti, I (Debrecen, Inst. Nucl. Res.) ; Nagy, Á (Debrecen, Inst. Nucl. Res.) ; Nyakó, B M (Debrecen, Inst. Nucl. Res.) ; Sas, N (Debrecen, Inst. Nucl. Res.) et al.
Electron-positron angular correlations were remeasured for the 17.6 MeV $(J^π = 1^+ \to 0^+)$ ground state transition in $^8Be$ using an improved setup compared to one we used previously. Significant deviations from the internal pair creation was observed at large angles in the angular correlations, which supports that, in an intermediate step, a neutral isoscalar particle with a mass of 17.0±0.5 (stat)±0.5 (sys) $MeV/c^2$ and $J^π = 1^+$ was created..
2017 - 7 p.
- Published in : EPJ Web Conf. 142 (2017) 01019
Fulltext: PDF;
In : International Symposium Advances in Dark Matter and Particle Physics, Messina, Italy, 24 - 27 Oct 2016, pp.01019
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5.
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New experimental results for the 17 MeV particle created in $^8Be$
/ Krasznahorkay, A J (Debrecen, Inst. Nucl. Res.) ; Csatlós, M (Debrecen, Inst. Nucl. Res.) ; Csige, L (Debrecen, Inst. Nucl. Res.) ; Gulyás, J (Debrecen, Inst. Nucl. Res.) ; Hunyadi, M (Debrecen, Inst. Nucl. Res.) ; Ketel, T J (NIKHEF, Amsterdam) ; Krasznahorkay, A (CERN ; MIT) ; Kuti, I (Debrecen, Inst. Nucl. Res.) ; Nagy, Á (Debrecen, Inst. Nucl. Res.) ; Nyakó, B M (Debrecen, Inst. Nucl. Res.) et al.
Electron-positron angular correlations were remeasured for the 17.6 MeV $(J^π = 1^+ \to 0^+)$ ground state transition in $^8Be$ using an improved setup compared to the one we used previously. Significant deviations from the internal pair creation was observed at large angles in the angular correlations, which supports that, in an intermediate step, a neutral isoscalar particle with a mass of 17.0 ±0.2(stat) ±0.5(sys) $MeV/c^2$ and $J^π = 1^+$ was created..
2017 - 7 p.
- Published in : EPJ Web Conf. 137 (2017) 08010
Fulltext: PDF;
In : 12th Quark Confinement and the Hadron Spectrum, Thessaloniki, Greece, 29 Aug - 2 Sep 2016, pp.08010
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6.
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A pair spectrometer for measuring multipolarities of energetic nuclear transitions
/ Gulyás, J. (Debrecen, Inst. Nucl. Res.) ; Ketel, T.J. (NIKHEF, Amsterdam) ; Krasznahorkay, A.J. (Debrecen, Inst. Nucl. Res.) ; Csatlós, M. (Debrecen, Inst. Nucl. Res.) ; Csige, L. (Debrecen, Inst. Nucl. Res.) ; Gácsi, Z. (Debrecen, Inst. Nucl. Res.) ; Hunyadi, M. (Debrecen, Inst. Nucl. Res.) ; Krasznahorkay, A. (CERN) ; Vitéz, A. (Debrecen, Inst. Nucl. Res.) ; Tornyi, T.G. (Debrecen, Inst. Nucl. Res.)
A multi-detector array has been designed and constructed for the simultaneous measurement of energy- and angular correlations of electron-positron pairs. Experimental results are obtained over a wide angular range for high-energy transitions in 16O, 12C and 8Be. [...]
arXiv:1504.00489.-
2016-02-01 - 8 p.
- Published in : Nucl. Instrum. Methods Phys. Res., A 808 (2016) 21-28
Fulltext: PDF; External link: Preprint
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7.
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Measurement of high energy gamma rays with large volume LaBr3(Ce) scintillators
/ Pellegri, L (Milan U. ; INFN, Milan) ; Brambilla, S (INFN, Milan) ; Riboldi, S (Milan U. ; INFN, Milan) ; Camera, F (Milan U. ; INFN, Milan) ; Giaz, AVMilan U. (INFN, Milan) ; Krasznahorkay, A (Debrecen, Inst. Nucl. Res.) ; Stuhl, L (Debrecen, Inst. Nucl. Res.) ; Csatlòs, M (Debrecen, Inst. Nucl. Res.) ; Gulyàs, J (Debrecen, Inst. Nucl. Res.) ; Benzoni, G (INFN, Milan) et al.
2012
Fulltext: PDF;
In : 13th international conference on nuclear reaction mechanisms, Villa Monastero, Varenna, Italy, 11 - 15 Jun 2012, pp.421
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The network of photodetectors and diode lasers of the CMS Link alignment system
/ Arce, P (Madrid, CIEMAT) ; Barcala, J M (Madrid, CIEMAT) ; Calvo, E (Madrid, CIEMAT) ; Ferrando, A (Madrid, CIEMAT) ; Josa, M I (Madrid, CIEMAT) ; Molinero, A (Madrid, CIEMAT) ; Navarrete, J (Madrid, CIEMAT) ; Oller, J C (Madrid, CIEMAT) ; Brochero, J (Cantabria U., Santander) ; Calderón, A (Cantabria U., Santander) et al.
The central feature of the CMS Link alignment system is a network of Amorphous Silicon Position Detectors distributed throughout the muon spectrometer that are connected by multiple laser lines. The data collected during the years from 2008 to 2015 is presented confirming an outstanding performance of the photo sensors during more than seven years of operation. [...]
2018 - 23 p.
- Published in : Nucl. Instrum. Methods Phys. Res., A 896 (2018) 1-23
Fulltext: PDF;
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