### Regular Series

#### Vol. 46 (2015), No. 1, pp. 1 – 215

all authors

C. Bloise, E. De Lucia, A. De Santis, P. De Simone, E. Czerwiński, A. Gajos, D. Kamińska, P. Moskal, M. Silarski, A. Di Domenico, A. Passeri, W. Wiślicki

Kaon Physics with the KLOE Detector

Acta Phys. Pol. B 46, 5 (2015)

page 5 •

abstract

In this paper, we discuss the recent finalized analyses by the KLOE experiment at DA$\Phi$NE: the CPT and Lorentz invariance test with entangled $K^{0}{\bar {K}^{0}}$ pairs, and the precision measurement of the branching fraction of the decay $K^+ \to \pi ^+\pi ^-\pi ^+(\gamma )$. We also present the status of an ongoing analysis aiming to precisely measure the $K^\pm$ mass.

Study of the $K_{\rm S}K_{\rm L}\to \pi \ell \nu 3\pi ^0$ Process for Time Reversal Symmetry Test at KLOE-2

Acta Phys. Pol. B 46, 13 (2015)

page 13 •

abstract

This work presents prospects for conducting a novel direct test of time-reversal symmetry at the KLOE-2 experiment. Quantum entanglement of neutral $K$ meson pairs uniquely available at KLOE-2 allows to probe directly the time-reversal symmetry ($\mathcal {T}$) independently of $\mathcal {CP}$ violation. This is achieved by a comparison of probabilities for a transition between flavour and $\mathcal {CP}$-definite states and its inverse obtained through exchange of initial and final states. As such, a test requires the reconstruction of the $K_{\rm L}\to 3\pi ^0$ decay accompanied by $K_{\rm S}\to \pi ^{\pm }\ell ^{\mp }\nu$ with good timing information, a new reconstruction method for this process is also presented which is capable of reconstructing the $K_{\rm L}\to 3\pi ^0$ decay with decay time resolution of $\mathcal {O}(1\tau _{\rm S})$.

$K_{\rm S}$ Semileptonic Decays and Test of CPT Symmetry with the KLOE Detector

Acta Phys. Pol. B 46, 19 (2015)

page 19 •

abstract

Study of semileptonic decays of neutral kaons allows to perform a test of discrete symmetries, as well as basic principles of the Standard Model. In this paper, a general review on dependency between charge asymmetry constructed for semileptonic decays of short- and long-lived kaons and $\mathcal {CPT}$ symmetry is given.

Improved $K_{\rm S}$ Tagging Procedure and Its Impact on Physics at KLOE-2

Acta Phys. Pol. B 46, 25 (2015)

page 25 •

abstract

The KLOE experiment at the DA$\Phi$NE $\phi$-factory performed precise studies of charged and neutral kaon physics, low energy QCD, as well as tests of CP and CPT invariance. For the new run, the KLOE has been upgraded by adding new tagger systems for the $\gamma \gamma$ physics, the inner tracking chamber and two calorimeters in the final focusing region. We are also improving on kaon identification techniques, in particular algorithms for the $K_{\rm S}$ meson tagging. In this article, we discuss the impact of the improved tagging procedure on studies of the $K_{\rm S}$ decays.

Study of the Dalitz Plot of the $\eta \rightarrow \pi ^+ \pi ^- \pi ^0$ Decay with the KLOE Detector

Acta Phys. Pol. B 46, 31 (2015)

page 31 •

abstract

The decay $\eta \rightarrow \pi ^+ \pi ^- \pi ^0$ is studied with the KLOE detector, at the DA$\Phi$NE $e^+e^-$ collider. Using a data sample corresponding to an integrated luminosity of $1.6$ fb$^{-1}$, a new study of the Dalitz plot is presented.

Search for the $U$ Boson in the Process $e^+e^- \to \mu ^+ \mu ^- \gamma$, $U \to \mu ^+\mu ^-$ with the KLOE Detector

Acta Phys. Pol. B 46, 39 (2015)

page 39 •

abstract

We present a search for a new light vector boson, carrier of a “dark force” between WIMPs, with the KLOE detector at DA$\Phi$NE. We analysed $e^+ e^- \to \mu ^+ \mu ^- \gamma$ ISR events corresponding to an integrated luminosity of $239$ pb$^{-1}$ to find evidence for the $e^+ e^- \to U\gamma$, $U\to \mu ^+\mu ^-$ process. We found no $U$ vector boson signal and set a 90% C.L. upper limit on the ratio of the $U$ boson and photon coupling constants between $1.6\times 10^{-5}$ to $8.6\times 10^{-7}$ in the mass region $520\lt M_{U}\lt 980$ MeV. A projection of the KLOE sensitivity for the $\mu \mu \gamma$ and $\pi \pi \gamma$ channels at full statistics and extended muon acceptance is also presented.

Measurement of Hadronic Cross Section at KLOE/KLOE-2

Acta Phys. Pol. B 46, 45 (2015)

page 45 •

abstract

The measurement of the $\sigma (e^+e^-\rightarrow \pi ^+\pi ^-)$ cross section allows to determine the pion form factor $\vert F_\pi \vert ^2$ and the two-pion contribution to the muon anomaly $a_\mu$. Such a measurement has been performed with the KLOE detector at DA$\Phi$NE, the Frascati $\phi$-factory. The preliminary results on the combination of the last analysis (KLOE12) with two previous published (KLOE08, KLOE10) will be presented in the following.

Studies of the $\omega$ Meson with the KLOE Detector

Acta Phys. Pol. B 46, 53 (2015)

page 53 •

abstract

The paper presents status of three studies involving the $\omega$ meson using data collected by the KLOE detector. The first two projects are feasibility studies performed on simulated data concerning an upper limit measurement of BR$(\phi \to \omega \gamma )$ and the form factor measurement in the $\omega \to \pi ^0l^+l^-$ Dalitz decay. The third study shows the effect $\pi ^0$–$\pi ^0$ interference has in the $\omega \to \pi ^+\pi ^-\pi ^0$ Dalitz plot when $\omega$ is produced through the $e^+e^-\to \omega \pi ^0$ channel.

Measurement of the Transition Form Factor in $\phi \to \pi ^0 e^+ e^-$ with the KLOE Detector

Acta Phys. Pol. B 46, 59 (2015)

page 59 •

abstract

By studying the invariant-mass distribution of the $e^+e^-$ in conversion decays, it is possible to learn more about mesons structure and underlying quark dynamics. At KLOE, the study of the $\phi \to \pi ^0 e^+e^-$ process is currently going to be finalized. At present, about 9000 events have been selected from a data sample of 1.7 fb$^{-1}$ from 2004/2005 data taking campaign. A very good agreement between data and Monte Carlo distributions has been achieved for all interesting kinematical variables. A preliminary invariant-mass spectrum of $e^{+}e^{-}$ is presented.

Search for the $U$ Boson in the Process $e^+ e^- \to U \gamma$, $U \to e^+ e^-$ with the KLOE Detector

Acta Phys. Pol. B 46, 65 (2015)

page 65 •

abstract

Dark Matter and Dark Energy are two of the most fundamental open questions in physics today. The existence of a light dark-force mediator has been hypothesized as a possible explanation for several unexplained physical phenomena. A new search for this mediator, the dark photon, $U$, is underway using data collected with the KLOE detector at DA$\Phi$NE. We describe the strategy we will use in our search for a resonant peak in the electron-positron invariant mass spectrum from the process $e^+e^- \to U \gamma$ with $U \to e^+e^-$. So far, we found no evidence for the process and set a preliminary upper limit on the level of mixing between the secluded dark sector and the Standard Model.

Commissioning of the Inner Tracker of the KLOE-2 Experiment

Acta Phys. Pol. B 46, 73 (2015)

page 73 •

abstract

The KLOE-2 experiment is undergoing commissioning at the DA$\Phi$NE $e^{+}e^{-}$ collider of the Frascati National Laboratory of the INFN, after the integration of new detectors in the former KLOE apparatus. The Inner Tracker, a very light detector (material budget $\lt 2\%X_{0}$), is one of the new subdetectors and it is composed of 4 cylindrical triple-GEM with a stereo XV-strips/pads readout. The commissioning phase of the Inner Tracker consists in the characterization of the detector response and in its performance evaluation. The method used to evaluate its detection efficiency is reported, together with some preliminary results.

all authors

D. Babusci, P. Ciambrone, M. Mascolo, R. Messi, D. Moricciani, S. Fiore, P. Gauzzi

Commissioning of the New Taggers of the KLOE-2 Experiment

Acta Phys. Pol. B 46, 81 (2015)

page 81 •

abstract

In order to fully reconstruct the $\gamma \gamma$ processes ($e^+e^- \to e^+e^- \gamma ^{\star }\gamma ^{\star }$) in the energy region of the $\phi$-meson production, new detectors along the DA$\Phi$NE beam line have been installed to detect the scattered $e^+e^-$.

Commissioning of the New Calorimeters of the KLOE-2 Experiment

Acta Phys. Pol. B 46, 87 (2015)

page 87 •

abstract

Three new sub-detectors have been installed on May 2013 in the KLOE apparatus of Laboratori Nazionali di Frascati of INFN. Photon detection is improved by means of a small crystal calorimeter, named CCALT, in the very forward direction and of a tungsten-scintillating tile sampling device, named QCALT, instrumenting the low-beta quadrupoles of the accelerator. During the first DA$\Phi$NE operations, some preliminary runs, both with and without collisions, have been acquired allowing the commissioning of new subdetectors. In this paper, we report a brief description of QCALT and CCALT, and a summary of the commissioning phase.

A New Event Display for the KLOE-2 Experiment

Acta Phys. Pol. B 46, 95 (2015)

page 95 •

abstract

In this contribution, we describe KNEDLE — the new event display for the KLOE-2 experiment. The basic objectives and software requirements are presented. The current status of the development is given along with a short discussion of the future plans.

all authors

J. Zmeskal, M. Sato, S. Ajimura, M. Bazzi, G. Beer, C. Berucci, H. Bhang, D. Bosnar, M. Bragadireanu, P. Buehler, L. Busso, M. Cargnelli, S. Choi, A. Clozza, C. Curceanu, A. D'Uffizi, S. Enomoto, L. Fabbietti, D. Faso, C. Fiorini, H. Fujioka, F. Ghio, R. Golser, C. Guaraldo, T. Hashimoto, R.S. Hayano, T. Hiraiwa, M. Iio, M. Iliescu, K. Inoue, S. Ishimoto, T. Ishiwatari, K. Itahashi, M. Iwai, M. Iwasaki, S. Kawasaki, J. Lachner, P. Levi Sandri, Y. Ma, J. Marton, Y. Matsuda, Y. Mizoi, O. Morra, P. Moskal, T. Nagae, H. Noumi, H. Ohnishi, S. Okada, H. Outa, D. Pietreanu, K. Piscicchia, M. Poli Lener, A. Romero Vidal, Y. Sada, A. Sakaguchi, F. Sakuma, E. Sbardella, A. Scordo, M. Sekimoto, H. Shi, M. Silarski, D. Sirghi, F. Sirghi, K. Suzuki, S. Suzuki, T. Suzuki, K. Tanida, H. Tatsuno, M. Tokuda, A. Toyoda, I. Tucakovic, K. Tsukada, O. Vazquez Doce, E. Widmann, T. Yamaga, T. Yamazaki, Q. Zhang

Measurement of the Strong Interaction Induced Shift and Width of the 1$s$ State of Kaonic Deuterium at J-PARC

Acta Phys. Pol. B 46, 101 (2015)

page 101 •

abstract

The antikaon–nucleon ($\overline {K}N$) interaction close to threshold provides crucial information on the interplay between spontaneous and explicit chiral symmetry breaking in low-energy QCD. In this context, the importance of kaonic deuterium X-ray spectroscopy has been well recognized, but no experimental results have yet been obtained due to the difficulty of the measurement. We propose to measure the shift and width of the kaonic deuterium $1s$ state with an accuracy of 60 eV and 140 eV, respectively, at J-PARC. These results, together with the kaonic hydrogen data (KpX at KEK, DEAR and SIDDHARTA at DA$\Phi$NE), will then permit the determination of values of both the isospin $I=0$ and $I=1$ antikaon–nucleon scattering lengths and will provide the most stringent constraints on the antikaon–nucleon interaction, promising a breakthrough. Refined Monte Carlo studies were performed, including the investigation of background suppression factors for the described setup. These studies have demonstrated the feasibility of determining the shift and width of the kaonic deuterium atom $1s$ state with the desired accuracy of 60 eV and 140 eV.

Unresolved Issues in the Search for Eta-mesic Nuclei

Acta Phys. Pol. B 46, 113 (2015)

page 113 •

abstract

Even if the theoretical definition of an unstable state is straightforward, its experimental identification often depends on the method used in the analysis and extraction of data. A good example is the case of eta-mesic nuclei where strong hints of their existence led to about three decades of extensive theoretical and experimental searches. Considering the still undecided status of these states and the limitations in the understanding of the eta–nucleon as well as the eta–nucleus interaction, the present article tries to look back at some unresolved problems in the production mechanism and final state interaction of the eta mesons and nuclei. An unconventional perspective which provides a physical insight into the nature of the eta–nucleus interaction is also presented using quantum time concepts.

Exotic Atoms and Exotic Nuclei

Acta Phys. Pol. B 46, 121 (2015)

page 121 •

abstract

In this article, we briefly review the study of the exotic atoms and exotic nuclei, and report on recent research activities of $\eta$-mesic nucleus and kaonic atoms.

all authors

H. Fujioka, Y. Ayyad, J. Benlliure, K.-T. Brinkmann, S. Friedrich, H. Geissel, J. Gellanki, C. Guo, E. Gutz, E. Haettner, M.N. Harakeh, R.S. Hayano, Y. Higashi, S. Hirenzaki, C. Hornung, Y. Igarashi, N. Ikeno, K. Itahashi, M. Iwasaki, D. Jido, N. Kalantar-Nayestanaki, R. Kanungo, R. Knoebel, N. Kurz, V. Metag, I. Mukha, T. Nagae, H. Nagahiro, M. Nanova, T. Nishi, H.J. Ong, S. Pietri, A. Prochazka, C. Rappold, M.P. Reiter, J.L. Rodríguez-Sánchez, C. Scheidenberger, H. Simon, B. Sitar, P. Strmen, B. Sun, K. Suzuki, I. Szarka, M. Takechi, Y.K. Tanaka, I. Tanihata, S. Terashima, Y.N. Watanabe, H. Weick, E. Widmann, J.S. Winfield, X. Xu, H. Yamakami, J. Zhao

Search for $\eta '$(958)–nucleus Bound States by $(p,d)$ Reaction at GSI and FAIR

Acta Phys. Pol. B 46, 127 (2015)

page 127 •

abstract

The mass of the $\eta '$ meson is theoretically expected to be reduced at finite density, which indicates the existence of $\eta '$–nucleus bound states. To investigate these states, we perform missing-mass spectroscopy for the $(p,d)$ reaction near the $\eta '$ production threshold. The overview of the experimental situation is given and the current status is discussed.

Luminosity Determination for the Deutron–Deutron Reactions Using Free and Quasi-free Reactions with WASA-at-COSY Detector

Acta Phys. Pol. B 46, 133 (2015)

page 133 •

abstract

Two methods of the luminosity determination for the experiment performed by the WASA Collaboration to search for $^4$He–$\eta$ bound state are presented. During the measurement, the technique of continuous change of the beam momentum in one accelerator cycle (called ramped beam) was applied. This imposes the requirement to determine not only the total integrated luminosity, but also its variation as a function of the beam momentum.

Version corrected according to Erratum Acta Phys. Pol. B 47, 571 (2016)

all authors

K. Piscicchia, C. Curceanu, S. Bartalucci, A. Bassi, S. Bertolucci, C. Berucci, A.M. Bragadireanu, M. Cargnelli, A. Clozza, L. De Paolis, S. Di Matteo, S. Donadi, A. D'Uffizi, J.-P. Egger, C. Guaraldo, M. Iliescu, T. Ishiwatari, M. Laubenstein, J. Marton, E. Milotti, D. Pietreanu, T. Ponta, E. Sbardella, A. Scordo, H. Shi, D.L. Sirghi, F. Sirghi, L. Sperandio, O. Vazquez Doce, J. Zmeskal

Beyond Quantum Mechanics? Hunting the ‘Impossible’ Atoms — Pauli Exclusion Principle Violation and Spontaneous Collapse of the Wave Function at Test

Acta Phys. Pol. B 46, 147 (2015)

page 147 •

abstract

The development of mathematically complete and consistent models solving the so-called “measurement problem”, strongly renewed the interest of the scientific community for the foundations of quantum mechanics, among these the Dynamical Reduction Models posses the unique characteristic to be experimentally testable. In the first part of the paper, an upper limit on the reduction rate parameter of such models will be obtained, based on the analysis of the X-ray spectrum emitted by an isolated slab of germanium and measured by the IGEX experiment. The second part of the paper is devoted to present the results of the VIP (Violation of the Pauli exclusion principle) experiment and to describe its recent upgrade. The VIP experiment established a limit on the probability that the Pauli Exclusion Principle (PEP) is violated by electrons, using the very clean method of searching for PEP forbidden atomic transitions in copper.

Determination of the COSY Proton Beam Polarization Using the WASA Detector

Acta Phys. Pol. B 46, 153 (2015)

page 153 •

abstract

The dynamics of $\eta$-meson production and the interaction of $\eta$ mesons with nucleons can be studied using the $\vec {p}p\to pp\eta$ reaction via measurements of the analyzing power $A_{y}$. To this end, we have performed a measurement of the $\vec {p}p\to pp\eta$ reaction using the WASA-at-COSY detector, which provides large acceptance and is $\varphi$-symmetric. The experiment was carried out for the beam momenta of $2026$ MeV/$c$ and $2188$ MeV/$c$. In this article, we present a method and results for the determination of the degree of the beam polarization.

The Chiral Long-range Two-pion Exchange Electromagnetic Currents in Radiative Nucleon–Deuteron Capture

Acta Phys. Pol. B 46, 159 (2015)

page 159 •

abstract

The nucleon–deuteron radiative capture process is investigated using the chiral nuclear potentials and the electromagnetic currents developed by the Bochum–Bonn group. While the strong interaction is taken up to the next-to-next-to-leading order, the electromagnetic current consists of a single nucleon current, the leading one-pion exchange one and is supplemented by contributions from the long-range two-pion exchange current at next-to-leading-order. The theoretical predictions for the cross sections as well as analyzing powers show strong dependence on the values of regularization parameters. Only small effects of the three-nucleon force and the long-range two-pion exchange current are observed. The dependence on the choice of regularization parameters results in a big theoretical uncertainty and clearly points to the necessity to include corrections from higher orders of the chiral expansion both for the nuclear forces and currents.

The Universe in the Light of LHC

Acta Phys. Pol. B 46, 169 (2015)

page 169 •

abstract

The Large Hadron Collider (LHC) provides data which give information on dark matter. Especially measurements related to the Higgs sector lead to strong constraints on the invisible sector which are competitive with the astrophysical limits. Some recent LHC results on the dark matter coming from the Higgs sector in the Inert Doublet Model (IDM) are presented.

The ELENA Project at CERN

Acta Phys. Pol. B 46, 181 (2015)

page 181 •

abstract

CERN has a longstanding tradition of pursuing fundamental physics on extreme low and high energy scales. The present physics knowledge is successfully described by the Standard Model and the General Relativity. In the anti-matter regime, many predictions of this established theory still remain experimentally unverified and one of the most fundamental open problems in physics concerns the question of asymmetry between particles: why is the observable and visible universe apparently composed almost entirely of matter and not of anti-matter? There is a huge interest in the very compelling scientific case for anti-hydrogen and low energy anti-proton physics, here to name especially the Workshop on New Opportunities in the Physics Landscape at CERN which was convened in May 2009 by the CERN Directorate and culminated in the decision for the final approval of the construction of the Extra Low ENergy Anti-proton (ELENA) ring by the Research Board in June 2011. ELENA is a CERN project aiming to construct a small 30 m circumference synchrotron to further decelerate anti-protons from the Anti-proton Decelerator (AD) from 5.3 MeV down to 100 keV.

all authors

D. Grzonka, K. Kilian, J. Ritman, T. Sefzick, W. Oelert, M. Diermaier, E. Widmann, J. Zmeskal, B. Głowacz, P. Moskal, M. Zieliński, M. Wolke, P. Nadel-Turonski, M. Carmignotto, T. Horn, H. Mkrtchyan, A. Asaturyan, A. Mkrtchyan, V. Tadevosyan, S. Zhamkochyan, S. Malbrunot-Ettenauer, W. Eyrich, F. Hauenstein, A. Zink

Search for Polarization Effects in the Antiproton Production Process

Acta Phys. Pol. B 46, 191 (2015)

page 191 •

abstract

For the production of a polarized antiproton beam, various methods have been suggested including the possibility that antiprotons may be produced polarized which will be checked experimentally. The polarization of antiprotons produced under typical conditions for antiproton beam preparation will be measured at the CERN/PS. If the production process creates some polarization, a polarized antiproton beam could be prepared by a rather simple modification of the antiproton beam facility. The detection setup and the expected experimental conditions are described.

all authors

C. Curceanu, K. Piscicchia, M. Bazzi, C. Berucci, D. Bosnar, A.M. Bragadireanu, A. Clozza, M. Cargnelli, A. D'Uffizi, L. Fabbietti, C. Fiorini, F. Ghio, C. Guaraldo, M. Iliescu, P. Levi Sandri, J. Marton, D. Pietreanu, M. Poli Lener, R. Quaglia, A. Romero Vidal, E. Sbardella, A. Scordo, H. Shi, D. Sirghi, F. Sirghi, M. Skurzok, I. Tucakovic, O. Vazquez Doce, E. Widmann, J. Zmeskal

Unprecedented Studies of the Low-energy Negatively Charged Kaons Interactions in Nuclear Matter by AMADEUS

Acta Phys. Pol. B 46, 203 (2015)

page 203 •

abstract

The AMADEUS experiment aims to provide unique quality data of $K^-$ hadronic interactions in light nuclear targets, in order to solve fundamental open questions in the non-perturbative strangeness QCD sector, like the controversial nature of the ${\mit \Lambda }(1405)$ state, the yield of hyperon formation below threshold, the yield and shape of multi-nucleon $K^-$ absorption, processes which are intimately connected to the possible existence of exotic antikaon multi-nucleon clusters. AMADEUS takes advantage of the DA$\Phi$NE collider, which provides a unique source of monochromatic low-momentum kaons and exploits the KLOE detector as an active target, in order to obtain excellent acceptance and resolution data for $K^-$ nuclear capture on H, ${}^4$He, ${}^{9}$Be and ${}^{12}$C, both at-rest and in-flight. During the second half of 2012, a successful data taking was performed with a dedicated pure carbon target implemented in the central region of KLOE, providing a high statistic sample of pure at-rest $K^-$ nuclear interactions. For the future, dedicated setups involving cryogenic gaseous targets are under preparation.

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