C. Curceanu

A New Measurement of Kaonic Hydrogen X-rays

The KN system at threshold is a sensitive testing ground for low energy QCD, especially for the explicit chiral symmetry breaking. Therefore, we have measured the K-series x rays of kaonic hydrogen atoms at the DANE electron-positron collider of Laboratori Nazionali di Frascati, and have de- termined the most precise values of the strong-interaction energy-level shift and width of the 1s atomic state. As x-ray detectors, we used large-area silicon drift detectors having excellent energy and timing resolution, which were developed especially for the SIDDHARTA experiment. The shift and width were determined to be ǫ1s = 283 ± 36(stat) ± 6(syst) eV and 1s = 541± 89(stat) ± 22(syst) eV, respectively. The new values will provide vital constraints on the theoretical description of the low-energy KN interaction.

Quantum explorations: from the waltz of the Pauli exclusion principle to the rock of the spontaneous collapse

The spin–statistics connection, in particular the Pauli exclusion principle (PEP), plays a very important role in our comprehension of matter and nature. Presently, the PEP violation, possible within some theories, generates a lively debate; it has given birth to a few experiments looking for tiny effects. The violation of the Pauli exclusion principle experiment put a very strong limit on the PEP violation probability by electrons, using the method of searching for PEP forbidden atomic transitions in a copper target. In this paper we present this experiment, the obtained results and future plans to upgrade the experimental setup with fast silicon drift detectors. We then present the idea of using an analogous experimental technique to search for x-rays as a signature of the spontaneous collapse of the wave function, predicted by the continuous spontaneous localization theories, and some very encouraging preliminary results.

Kaonic hydrogen X-ray measurement in SIDDHARTA

Abstract Kaonic hydrogen atoms provide a unique laboratory to probe the kaon–nucleon strong interaction at the energy threshold, allowing an investigation of the interplay between spontaneous and explicit chiral symmetry breaking in low-energy QCD. The SIDDHARTA Collaboration has measured the K -series X rays of kaonic hydrogen atoms at the DAΦNE electron–positron collider of Laboratori Nazionali di Frascati, and has determined the most precise values of the strong-interaction induced shift and width of the 1 s atomic energy level. This result provides vital constraints on the theoretical description of the low-energy K ¯ N interaction.

Precision measurement of the 3d → 2p x-ray energy in kaonic 4He

Abstract We have measured the Balmer-series x-rays of kaonic 4 He atoms using novel large-area silicon drift x-ray detectors in order to study the low-energy K ¯ -nucleus strong interaction. The energy of the 3 d → 2 p transition was determined to be 6467 ± 3 ( stat ) ± 2 ( syst ) eV . The resulting strong-interaction energy-level shift is in agreement with theoretical calculations, thus eliminating a long-standing discrepancy between theory and experiment.

New experimental limit on the Pauli exclusion principle violation by electrons

The Pauli Exclusion Principle (PEP) is one of the basic principles of modern physics and, even if there are no compelling reasons to doubt its validity, it is still debated today because an intuitive, elementary explanation is still missing, and because of its unique stand among the basic symmetries of physics. The present paper reports a new limit on the probability that PEP is violated by electrons, in a search for a shifted K

First measurement of kaonic helium-3 X-rays

_\alpha

Search for the deeply bound K–pp state from the semi-inclusive forward-neutron spectrum in the in-flight K– reaction on helium-3

line in copper: the presence of this line in the soft X-ray copper fluorescence would signal a transition to a ground state already occupied by 2 electrons. The obtained value,

Preliminary study of kaonic deuterium X-rays by the SIDDHARTA experiment at DAΦNE

{1/2} \beta^{2} \leq 4.5\times 10^{-28}

Measurements of the strong-interaction widths of the kaonic 3He and 4He 2p levels

, improves the existing limit by almost two orders of magnitude.

Revealing Bell's Nonlocality for Unstable Systems in High Energy Physics

The first observation of the kaonic 3He 3d→2p transition was made, using slow K− mesons stopped in a gaseous 3He target. The kaonic atom X-rays were detected with large-area silicon drift detectors using the timing information of the K+K− pairs of ϕ-meson decays produced by the DAΦNE e+e− collider. The strong interaction shift of the kaonic 3He 2p state was determined to be −2±2(stat)±4(syst) eV.Scattering of fermion off dilaton black hole has been extensively studied over the years [1–3, 5–11] and it has provided much insight into its connection to the Hawking radiation. Even after the intensive investigations it remains as a subject of several interests because of the subtleties involved in it in connection with information loss scenario during the formation and subsequent evaporation of black hole. It is worth mentioning at this stage that a controversy in this context was generated from the Hawking’s suggestion [1] three decades ago. However his recent suggestion on this issue [4] has brought back a pretty pleasant scenario. It may even be thought that the controversy has come to an end. General description of such scattering problem is extremely difficult. Despite that, there have been attempts in studying such problem in its full complexity through the s-matrix description of such event [2]. Comparatively less complicated model therefore entered into the picture and showed its prominent role in this issue [5–9]. The toy model due to Alford and Strominger [5] provides an interesting description of the s-wave scattering of fermion off dilaton black hole with a trustworthy results concerning information loss. It helps to avoid some of the technical obstacle posed by quantum gravity in (3 + 1). Even in the presence of gravitational anomaly a systematic description of this scattering of fermion off dilaton would have been possible through this model [10, 11]. The provision of taking the effect of one loop correction [12, 13] into consideration is also an exiting aspect of this model. That indeed shows a way to investigate the effect of anomaly [10, 11] on this scattering phenomena. Notably, this model arose in two dimensional non-critical string theory and its black hole solution was discovered in [14]. Few years back Mitra studied this scattering problem replacing Dirac fermion by chiral fermion and found an uncomfortable scenario [10]. He observed that information failed to be preserved. With the use of anomaly we have shown that that disaster can be avoided [11]. Anomaly played there a very surprising as well as interesting role. Seeing the interesting role of anomaly on the s-wave scattering of chiral fermion [10, 11] we are intended here to investigate the role of one loop correction on the s-wave scattering of Dirac fermion using the said toy model due to Alford and Strominger [5]. Needless to mention that the counter term appeared here due to one loop correction looks similar to the term used in [11].