This title appears in the Scientific Report : 2017 

Importance of d-wave contributions in the charge symmetry breaking reaction $dd \to {}^4\text{He}\pi^0$
Adlarson, P.
Augustyniak, W. / Bardan, W. / Bashkanov, M. / Bergmann, F. S. / Berłowski, M. / Bondar, A. / Büscher, M. / Calén, H. / Ciepał, I. / Clement, H. / Czerwiński, E. / Demmich, K. / Engels, Ralf W. / Erven, A. / Erven, W. / Eyrich, W. / Fedorets, P. / Föhl, K. / Fransson, K. / Goldenbaum, F. / Goswami, A. / Grigoryev, K. / Gullström, C. -O. / Hanhart, C. / Heijkenskjöld, L. / Hejny, V. / Hüsken, N. / Jarczyk, L. / Johansson, T. / Kamys, B. / Kemmerling, G. / Khatri, G. / Khoukaz, A. / Khreptak, O. / Kirillov, D. A. / Kistryn, S. / Kleines, H. / Kłos, B. / Krzemień, W. / Kulessa, P. / Kupść, A. / Kuzmin, A. / Lalwani, K. / Lersch, D. / Lorentz, B. / Magiera, A. / Maier, R. / Marciniewski, P. / Mariański, B. / Morsch, H. -P. / Moskal, P. / Ohm, H. / Parol, W. / del Rio, E. Perez / Piskunov, N. M. / Prasuhn, D. / Pszczel, D. / Pysz, K. / Pyszniak, A. / Ritman, J. / Roy, A. / Rudy, Z. / Rundel, O. / Sawant, S. / Schadmand, S. / Schätti-Ozerianska, I. / Sefzick, T. / Serdyuk, V. / Shwartz, B. / Sitterberg, K. / Skorodko, T. / Skurzok, M. / Smyrski, J. / Sopov, V. / Stassen, R. / Stepaniak, J. / Stephan, E. / Sterzenbach, G. / Stockhorst, H. / Stroeher, Hans / Szczurek, A. / Trzciński, A. / Wolke, M. / Wrońska, A. / Wüstner, P. / Yamamoto, A. / Zabierowski, J. / Zieliński, M. J. / Złomańczuk, J. / Żuprański, P. / Zurek, Maria (Corresponding author)
IKP- Technische und Administrative Infrastruktur; IKP-TA
Kernphysikalische Großgeräte; IKP-4
Theorie der starken Wechselwirkung; IKP-3
Theorie der Starken Wechselwirkung; IAS-4
Experimentelle Hadronstruktur; IKP-1
Zentralinstitut für Elektronik; ZEA-2
Experimentelle Hadrondynamik; IKP-2
2017
Preprint
Accelerator R & D
Cosmic Matter in the Laboratory
Get full text
OpenAccess
OpenAccess
Please use the identifier: http://hdl.handle.net/2128/15257 in citations.
This letter reports the first measurement of the contribution of higher partial waves in the charge symmetry breaking reaction $dd \to {}^4\text{He}\pi^0$ using the WASA-at-COSY detector setup at an excess energy of $Q = 60$ MeV. The determined differential cross section can be parametrized as $\text{d}\sigma/\text{d}\Omega = a + b\cos^{2}\theta^*$, where $\theta^*$ is the production angle of the pion in the center-of-mass coordinate system, and the results for the parameters are $a = \left(1.55 \pm 0.46 (\text{stat}) ^{+0.32}_{-0.8} (\text{syst}) \right) \text{pb/sr}$ and $b = \left(13.1 \pm 2.1 (\text{stat}) ^{+1.0}_{-2.7} (\text{syst})\right) \text{pb/sr}$. The data are compatible with vanishing $p$-waves and a sizable $d$-wave contribution. This finding should strongly constrain the contribution of the $\Delta$ isobar to the $dd \to {}^4\text{He}\pi^0$ reaction and is therefore crucial for a quantitative understanding of quark mass effects in nuclear production reactions.