Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Kaonic 3He and 4He X-ray measurements in SIDDHARTA   The strong-interaction shift of kaonic 3He and 4He 2p states was measured
using gaseous targets for the first time in the SIDDHARTA experiment. The
determined shift of kaonic 4He is much smaller than the values obtained in the
experiments performed in 70's and 80's. Thus, the problems in kaonic helium
(the "kaonic helium puzzle") was definitely solved by our measurements. The
first observation of the kaonic 3He X-rays was also achieved. The shift both of
kaonic 3He and 4He was found to be as small as a few eV.

19
The categories of this paper are: eess
23
The categories of this paper are: solv-int
13
The categories of this paper are: quant-ph
20
The categories of this paper are: acc-phys
35
The categories of this paper are: mtrl-th
28
The categories of this paper are: alg-geom
3
The categories of this paper are: physics
30
The categories of this paper are: q-alg
8
The categories of this paper are: hep-ex
12
The categories of this paper are: nucl-th
34
The categories of this paper are: chem-ph
37
The categories of this paper are: supr-con
2
The categories of this paper are: math
29
The categories of this paper are: funct-an
11
The categories of this paper are: hep-lat
14
The categories of this paper are: math-ph