Probing the chiral magnetic wave with charge-dependent flow measurements in Pb-Pb collisions at the LHC

The Chiral MagneticWave (CMW) phenomenon is essential to provide insights into the strong interaction in QCD, the properties of the quark-gluon plasma, and the topological characteristics of the early universe, offering a deeper understanding of fundamental physics in high-energy collisions. Measurements of the charge-dependent anisotropic flow coefficients are studied in Pb-Pb collisions at center-of-mass energy per nucleon-nucleon collision v sNN = 5.02TeV to probe the CMW. In particular, the slope of the normalized difference in elliptic (v2) and triangular (v3) flow coefficients of positively and negatively charged particles as a function of their event-wise normalized number difference, is reported for inclusive and identified particles. The slope rNorm 3 is found to be larger than zero and to have a magnitude similar to rNorm 2, thus pointing to a large background contribution for these measurements. Furthermore, rNorm 2 can be described by a blast wave model calculation that incorporates local charge conservation. In addition, using the event shape engineering technique yields a fraction of CMW (fCMW) contribution to this measurement which is compatible with zero. This measurement provides the very first upper limit for fCMW, and in the 10-60% centrality interval it is found to be 26% (38%) at 95% (99.7%) confidence level

Hydrogen Bonding and Electron Donor-Acceptor (EDA) Interactions Controlling the Crystal Packing of Picric Acid and Its Adducts with Nitrogen Bases. Their Rationalization in Terms of the pKa Equalization and Electron-Pair Saturation Concepts

The structures of picric acid and 14 of its adducts with N-bases were determined by X-ray diffraction. All intermolecular contacts shorter than the sum of the van der Waals radii were retrieved, classified as 81 conventional X-H...:Y (X,Y = N,O) and 108 weaker C-H...:O H-bonds and as 49 C/N<--:O pi*<--n or pi*(k)<--n and four C<--:C pi*<--pi electron donor-acceptor (EDA) interactions, and carefully scrutinized to single out the general rules (if any) the 242 contacts are conforming to. X...Y distances and related E(HB) energies of the 81 X-H...:Y bonds are found to correlate with Delta(pKa) = pKa(X-H)-pKa(Y-H+), validating the pKa equalization principle for which strong H-bonds occur only when Delta(pKa) tends to zero. Moreover, by redefining all X/C-H...:Y bonds as X/C-H<--:Y sigma*<--n EDA interactions, all contacts become EDA interactions, leading to formulate the electron-pair saturation rule for which “all electron donors of a closed-shell molecule (nonbonding pairs of lone pairs or pi-bonding pairs of multiple bonds) become engaged in EDA interactions with the electron acceptors (X-H, C-H, pi*(k), or pi*) present, as far as they are available; when the acceptors are insufficient, they are saturated in order of decreasing EDA interaction strength”. It is shown that this novel rule provides a particularly easy way to look at crystal packing