$$\Lambda _b \rightarrow \pi ^- (D_s^-) \Lambda _c(2595),~\pi ^- (D_s^-) \Lambda _c(2625)$$ decays and $$DN,~D^*N$$DN,D∗N molecular components

From the perspective that \(\Lambda _c(2595)\) and \(\Lambda _c(2625)\) are dynamically generated resonances from the \(DN,~D^*N\) interaction and coupled channels, we have evaluated the rates for \(\Lambda _b \rightarrow \pi ^- \Lambda _c(2595)\) and \(\Lambda _b \rightarrow \pi ^- \Lambda _c(2625)\) up to a global unknown factor that allows us to calculate the ratio of rates and compare with experiment, where good agreement is found. Similarly, we can also make predictions for the ratio of rates of the, yet unknown, decays of \(\Lambda _b \rightarrow D_s^- \Lambda _c(2595)\) and \(\Lambda _b \rightarrow D_s^- \Lambda _c(2625)\) and make estimates for their individual branching fractions.     

Lifetime measurements in $$^{182}\hbox {Pt}$$ using $$\gamma $$ – $$\gamma $$ fast-timing

The European Physical Journal A - In this paper, we discuss the evolution of breakup models from fully quantum mechanical, such as the Ichimura–Austern–Vincent model to semiclassical,...     

Spin density matrix of the $$\omega $$ in the reaction $${\bar{p}p}\,\rightarrow \,\omega \pi ^0$$p¯p→π0

The spin density matrix of the \(\omega \) has been determined for the reaction \({\bar{p}p}\,\rightarrow \,\omega \pi ^0\) with unpolarized in-flight data measured by the Crystal Barrel LEAR experiment at CERN. The two main decay modes of the \(\omega \) into \(\pi ^0 \gamma \) and \(\pi ^+ \pi ^- \pi ^0\) have been separately analyzed for various \({\bar{p}}\)momenta between 600 and 1940 MeV/c. The results obtained with the usual method by extracting the matrix elements via the \(\omega \) decay angular distributions and with the more sophisticated method via a full partial wave analysis are in good agreement. A strong spin alignment of the \(\omega \) is clearly visible in this energy regime and all individual spin density matrix elements exhibit an oscillatory dependence on the production angle. In addition, the largest contributing orbital angular momentum of the \({\bar{p}p~}\)system has been identified for the different beam momenta. It increases from \(L^{max}_{{\bar{p}p~}}\) \(=\) 2 at 600 MeV/c to \(L^{max}_{{\bar{p}p~}}\) \(=\) 5 at 1940 MeV/c.     

Are $B\rightarrow\pi K$ CP-asymmetries quantized?

A search for patterns in the numerous B-decay modes now available is necessary in order to test the Cabibbo-Kobayashi-Maskawa theory of CP-violation. In particular, the well-structured pattern of branching ratios may lead to a quantized spectrum for direct CP-asymmetries, providing in this way a rather unique opportunity to discriminate between hadronic final state interaction models.Arrival of the final proofs: 25 June 2003     

Predictions for $$\Xi _b^- \rightarrow \pi ^- (D_s^- ) \ \Xi _c^0 (2790) \left( \Xi _c^0 (2815) \right) $$ and $$\Xi _b^- \rightarrow \bar{\nu }_l l \ \Xi _c^0 (2790) \left( \Xi _c^0 (2815) \right) $$Ξb-→ν¯llΞc0(2790)Ξc0(2815)

We have performed calculations for the nonleptonic \(\Xi _b^- \rightarrow \pi ^- \ \Xi _c^0 (2790) \left( J=\frac{1}{2}\right) \) and \(\Xi _b^- \rightarrow \pi ^- \ \Xi _c^0 (2815) \left( J=\frac{3}{2}\right) \) decays and the same reactions replacing the \(\pi ^-\) by a \(D_s^-\). At the same time we have also evaluated the semileptonic rates for \(\Xi _b^- \rightarrow \bar{\nu }_l l \ \Xi _c^0 (2790)\) and \(\Xi _b^- \rightarrow \bar{\nu }_l l \ \Xi _c^0 (2815)\). We look at the reactions from the perspective that the \(\Xi _c^0 (2790)\) and \(\Xi _c^0 (2815)\) resonances are dynamically generated from the pseudoscalar–baryon and vector–baryon interactions. We evaluate ratios of the rates of these reactions and make predictions that can be tested in future experiments. We also find that the results are rather sensitive to the coupling of the \(\Xi _c^*\) resonances to the \(D^* \Sigma \) and \(D^* \Lambda \) components.     

Experimental determination of the branching ratiosp\bar p \to 2\pi ^0 ,\pi ^0 \gamma,and 2γ at rest

The branching ratios of \(p\bar p\) annihilations into the neutral final states 2π⁰, π⁰γ, and 2γ are measured by stopping antiprotons in liquid hydrogen. They are \(B_{2\pi ^0 } = \left( {2.06 \pm 0.14} \right) \times 10^{ - 4} \) , \(B_{\pi ^0 \gamma } = \left( {1.74 \pm 0.22} \right) \times 10^{ - 5} \) , andB _γγ<1.7×10^?6 (95% c.l.).     

Spin correlations in the ΛΛ and Λ$$ \bar \Lambda $$ systems generated in relativistic heavy-ion collisions

Spin correlations for the ΛΛ and Λ$ \bar \Lambda $ \bar \Lambda pairs, generated in relativistic heavy-ion collisions, and related angular correlations at the joint registration of hadronic decays of two hyperons, in which space parity is not conserved, are analyzed. The correlation tensor components can be derived from the double angular distribution of products of two decays by the method of “moments”. The properties of the “trace” of the correlation tensor (a sum of three diagonal components), determining the relative fractions of the triplet states and singlet state of respective pairs, are discussed. Spin correlations for two identical particles (ΛΛ) and two nonidentical particles (Λ$ \bar \Lambda $ \bar \Lambda ) are considered from the viewpoint of the conventional model of one-particle sources. In the framework of this model, correlations vanish at sufficiently large relative momenta. However, under these conditions, in the case of two nonidentical particles (Λ$ \bar \Lambda $ \bar \Lambda ) a noticeable role is played by two-particle annihilation (two-quark, two-gluon) sources, which lead to the difference of the correlation tensor from zero. In particular, such a situation may arise when the system passes through the “mixed phase.”     

Strong decay of $$\Lambda _c(2940)$$ as a 2 P state in the $$\Lambda _c$$Λc family

Considering the mass, parity and \(D^0 p\) decay mode, we tentatively assign the \(\Lambda _c(2940)\) as the \(P-\)wave states with one radial excitation. Then, via studying the strong decay behavior of the \(\Lambda _c(2940)\) within the \(^3P_0\) model, we obtain that the total decay widths of the \(\Lambda _{c1}(\frac{1}{2}^-,2P)\) and \(\Lambda _{c1}(\frac{3}{2}^-,2P)\) states are 16.27 and 25.39 MeV, respectively. Compared with the experimental total width \(27.7^{+8.2}_{-6.0}\pm 0.9^{+5.2}_{-10.4}~\mathrm {MeV}\) measured by LHCb Collaboration, both assignments are allowed, and the \(J^P=\frac{3}{2}^-\) assignment is more favorable. Other \(\lambda \)-mode \(\Sigma _c(2P)\) states are also investigated, which are most likely to be narrow states and have good potential to be observed in future experiments.     

$$f_0(500)$$, $$f_0(980)$$f0(980), and $$a_0(980)$$a0(980) production in the $$\chi _{c1} \rightarrow \eta \pi ^+\pi ^-$$χc1→ηπ+π- reaction

We study the \(\chi _{c1} \rightarrow \eta \pi ^+ \pi ^-\) decay, paying attention to the production of \(f_0(500)\), \(f_0(980)\), and \(a_0(980)\) from the final state interaction of pairs of mesons that can lead to these three mesons in the final state, which is implemented using the chiral unitary approach. Very clean and strong signals are obtained for the \(a_0(980)\) excitation in the \(\eta \pi \) invariant mass distribution and for the \(f_0(500)\) in the \(\pi ^+ \pi ^-\) mass distribution. A smaller, but also clear signal for the \(f_0(980)\) excitation is obtained. The results are contrasted with experimental data and the agreement found is good, providing yet one more test in support of the picture where these resonances are dynamically generated from the meson–meson interaction.     

Search for H → WW → $$\ell \nu \ell \nu $$ Decays of a Heavy Higgs Boson Produced in pp Collisions at $$\sqrt s $$ = 13 TeV Using a 139-fb–1 Event Sample Recorded by the ATLAS Experiment

Physics of Atomic Nuclei - Events with final-state electron and muon pairs produced in pp collisions at $$\sqrt s $$ = 13 TeV are analyzed toward detecting H → WW → $$\ell \nu \ell \nu...     

Rare kaon decay $$K^ + \to \pi ^ + \nu \bar \nu $$ in S U(3)C ⊗ S U(3)L ⊗ U(1)N models

The rare kaon decay \(K^ + \to \pi ^ + \nu \bar \nu \) is considered in the framework of models based on the SU(3) _C ? SU(3) _L ? U(1) _N (3-3-1) gauge group. In the 3-3-1 model with right-handed neutrinos, the lower bound of the Z’ mass is derived at 3 TeV, and that in the minimal version, at 1.7 TeV.     

The decays of $$\bar{B}^0$$, $$\bar{B}^0_s$$B¯s0 and $$B^-$$B- into $$\eta _c$$ηc plus a scalar or vector meson

We investigate the decays of \(\bar{B}^0_s\), \(\bar{B}^0\) and \(B^-\) into \(\eta _c\) plus a scalar or vector meson in a theoretical framework by taking into account the dominant process for the weak decay of \(\bar{B}\) meson into \(\eta _c\) and a \(q\bar{q}\) pair. After hadronization of this \(q\bar{q}\) component into pairs of pseudoscalar mesons we obtain certain weights for the pseudoscalar meson-pseudoscalar meson components. In addition, the \(\bar{B}^0\) and \(\bar{B}^0_s\) decays into \(\eta _c\) and \(\rho ^0\), \(K^*\) are evaluated and compared to the \(\eta _c\) and \(\phi \) production. The calculation is based on the postulation that the scalar mesons \(f_0(500)\), \(f_0(980)\) and \(a_0(980)\) are dynamically generated states from the pseudoscalar meson-pseudoscalar meson interactions in S-wave. Up to a global normalization factor, the \(\pi \pi \), \(K \bar{K}\) and \(\pi \eta \) invariant mass distributions for the decays of \(\bar{B}^0_s \rightarrow \eta _c \pi ^+ \pi ^-\), \(\bar{B}^0_s \rightarrow \eta _c K^+ K^-\), \(\bar{B}^0 \rightarrow \eta _c \pi ^+ \pi ^-\), \(\bar{B}^0 \rightarrow \eta _c K^+ K^-\), \(\bar{B}^0 \rightarrow \eta _c \pi ^0 \eta \), \(B^- \rightarrow \eta _c K^0 K^-\) and \(B^- \rightarrow \eta _c \pi ^- \eta \) are predicted. Comparison is made with the limited experimental information available and other theoretical calcualtions. Further comparison of these results with coming LHCb measurements will be very valuable to make progress in our understanding of the nature of the low lying scalar mesons, \(f_0(500), f_0(980)\) and \(a_0(980)\).     

One-pot synthesis of $$\upgamma $$-spiroiminolactones and $$\upgamma $$-dispiroiminolactones using $$\textit{N}{,}{} \textit{N}^{\prime }$$N,N′-disubstituted parabanic acid and thioparabanic acid derivatives

A direct entry and simple process for the synthesis of \(\upgamma \)-spiroiminolactones present in a large number of natural products has been developed. In the first step, the synthesis of parabanic acid derivatives was commenced from the reaction of \(\textit{N}{,}{} \textit{N}^{\prime }\)-disubstituted urea and thiourea with oxalyl chloride, then a three-component reaction was carried out with isocyanides, acetylenic esters, and \(\textit{N}{,}{} \textit{N}^{\prime }\)-disubstituted parabanic acid derivatives. The method allows the construction of a variety of \(\upgamma \)-spiroiminolactone structures in good to high yields starting from readily available precursors. It was found that in the case of \(\textit{N}{,}{} \textit{N}^{\prime }\)-diphenyl thioparabanic acid, additional products of \(\upgamma \)-dispiroiminolactones have been formed due to the higher electrophilicity of \(\upalpha \)-dicarbonyl groups. The structures were fully established using spectroscopic analysis NMR, IR, and Mass spectrometry. The crystal structure of \(\upgamma \)-dispiroiminolactone was confirmed from single-crystal X-ray diffraction study.     

Determinations of $$|V_{cb}|$$ and $$|V_{ub}|$$|Vub| from baryonic $$\Lambda _b$$Λb decays

We present the first attempt to extract \(|V_{cb}|\) from the \(\Lambda _b\rightarrow \Lambda _c^+\ell \bar{\nu }_\ell \) decay without relying on \(|V_{ub}|\) inputs from the B meson decays. Meanwhile, the hadronic \(\Lambda _b\rightarrow \Lambda _c M_{(c)}\) decays with \(M=(\pi ^-,K^-)\) and \(M_c=(D^-,D^-_s)\) measured with high precisions are involved in the extraction. Explicitly, we find that \(|V_{cb}|=(44.6\pm 3.2)\times 10^{-3}\), agreeing with the value of \((42.11\pm 0.74)\times 10^{-3}\) from the inclusive \(B\rightarrow X_c\ell \bar{\nu }_\ell \) decays. Furthermore, based on the most recent ratio of \(|V_{ub}|/|V_{cb}|\) from the exclusive modes, we obtain \(|V_{ub}|=(4.3\pm 0.4)\times 10^{-3}\), which is close to the value of \((4.49\pm 0.24)\times 10^{-3}\) from the inclusive \(B\rightarrow X_u\ell \bar{\nu }_\ell \) decays. We conclude that our determinations of \(|V_{cb}|\) and \(|V_{ub}|\) favor the corresponding inclusive extractions in the B decays.     

Prospects for constrained supersymmetry at $$\sqrt{s}={33}\,\text {TeV} $$ and $$\sqrt{s}={100}\,\text {TeV} $$ proton–proton super-colliders

Successful models of pure gravity mediation (PGM) with radiative electroweak symmetry breaking can be expressed with as few as two free parameters, which can be taken as the gravitino mass and \(\tan \beta \) . These models easily support a 125–126 GeV Higgs mass at the expense of a scalar spectrum in the multi-TeV range and a much lighter wino as the lightest supersymmetric particle. In these models, it is also quite generic that the Higgs mixing mass parameter, \(\mu \) , which is determined by the minimization of the Higgs potential is also in the multi-TeV range. For \(\mu >0\) , the thermal relic density of winos is too small to account for the dark matter. The same is true for \(\mu <0\) unless the gravitino mass is of order 500 TeV. Here, we consider the origin of a multi-TeV \(\mu \) parameter arising from the breakdown of a Peccei–Quinn (PQ) symmetry. A coupling of the PQ-symmetry breaking field, \(P\) , to the MSSM Higgs doublets, naturally leads to a value of \(\mu \sim \langle P \rangle ^2 /M_P \sim {\mathcal O}(100)\) TeV and of the order that is required in PGM models. In this case, axions make up the dark matter or some fraction of the dark matter with the remainder made up from thermal or non-thermal winos. We also provide solutions to the problem of isocurvature fluctuations with axion dark matter in this context.