arXiv subjects

Marek Karliner

Publications and source records attributed to Marek Karliner.

At least 55 records · Page 3Linked to original sources

arXiv2013

Generalized Skyrmions in QCD and the Electroweak Sector

We discuss the stability and masses of topological solitons in QCD and strongly-interacting models of electroweak symmetry breaking with arbitrary combinations of two inequivalent Lagrangian terms of fourth order in the field spatial derivatives. We find stable solitons for only a restricted range of the ratio of these combinations, in agreement with previous results, and we calculate the corresponding soliton masses. In QCD, the experimental constraints on the fourth-order terms force the soliton to resemble the original Skyrmion solution. However, this is not necessarily the case in strongly-interacting models of electroweak symmetry breaking, in which a non-Skyrmion-like soliton is also possible. This possibility will be constrained by future LHC measurements and dark matter experiments. Current upper bounds on the electroweak soliton mass range between 18 and 59 TeV, which would be reduced to 4.6 to 8.1 TeV with the likely sensitivity of LHC data to the fourth-order electroweak Lagrangian parameters.

hep-ph↗

arXiv2013

Puzzles in Hadronic Physics and Novel Quantum Chromodynamics Phenomenology

We review some outstanding puzzles and experimental anomalies in hadron physics that appear to challenge conventional wisdom and, in some cases, the foundations of QCD. We also discuss possible solutions and propose new tests and experiments that could illuminate the underlying physics and novel phenomenological features of QCD. In some cases, new perspectives for QCD physics have emerged.

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arXiv2012

Indications on the Mass of the Lightest Electroweak Baryon

In general, an effective low-energy Lagrangian model of composite electroweak symmetry breaking contains soliton solutions that may be identified with technibaryons. We recall how the masses of such states may be related to the coefficients of fourth-order terms in the effective Lagrangian, and review the qualitative success of this approach for baryons in QCD. We then show how the current theoretical and phenomenological constraints on the corresponding fourth-order coefficients in the electroweak theory could be used to estimate qualitative lower and upper bounds on the lightest electroweak baryon mass. We also discuss how the sensitivity of the LHC experiments could enable these bounds to be improved.

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arXiv2011

Heavy Baryons and Exotics Spectrum

We discuss several highly accurate theoretical predictions for masses of baryons containing the b quark which have been recently confirmed by experimental data. Several predictions are given for additional properties of heavy baryons. We also discuss the two charged exotic resonances Z_b with quantum numbers of a (b bbar u ddbar) tetraquark, very recently reported by Belle in the channel [Upsilon(nS) π^+, n=1,2,3]. Among possible implications are deeply bound I=0 counterparts of the Z_b-s and existence of a Sigma_b^+ Sigma_b^- dibaryon, a "beauteron".

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arXiv2010

Isospin Violation in X(3872): Explanation From a New Tetraquark Model

New data for X(3872) production in B decays provide a separation between X production and decay, sharpen several experimental puzzles and impose serious constraints on all models. Both charged and neutral B decays produce a narrow neutral resonant state that decays to both J/ψρand J/ψω, while no charged resonances in the same multiplet are found. This suggests that the X is an isoscalar resonance whose production conserves isospin, while isospin is violated only in the decay by an electromagnetic interaction allowing the isospin-forbidden J/ψρdecay. A tetraquark isoscalar X model is proposed which agrees with all present data, conserves isospin in its production and breaks isospin only in an electromagnetic X(3872) --> J/ψρ^o decay. The narrow X decay width results from the tiny phase space available for the J/ψωdecay and enables competition with the electromagnetic isospin-forbidden J/ψρdecay which has much larger phase space. Experimental tests are proposed for this isospin production invariance.

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arXiv2010

About a Possible Nonstrange Cousin of the Theta+ Pentaquark

We discuss the implications of the suggested interpretation of the recently reported narrow pi N resonance (width \approx 25 MeV at 1680 MeV) as a pentaquark in the same multiplet as the Theta+. We consider a diquark-triquark pentaquark model involving a recoupling of the five quarks into a diquark-triquark system in non-standard color representations. We estimate the mass using a well-tested simple mass formula. Our rough numerical estimate puts the pi N pentaquark resonance at 1720 MeV, sufficiently close to the reported value of 1680 MeV to indicate that this approach deserves further more accurate investigation.

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arXiv2009

Review of Rotational Symmetry Breaking in Baby Skyrme Models

We discuss one of the most interesting phenomena exhibited by baby skyrmions -- breaking of rotational symmetry. The topics we will deal with here include the appearance of rotational symmetry breaking in the static solutions of baby Skyrme models, both in flat as well as in curved spaces, the zero-temperature crystalline structure of baby skyrmions, and finally, the appearance of spontaneous breaking of rotational symmetry in rotating baby skyrmions.

hep-th↗

arXiv2008

Heavy quark spectroscopy and prediction of bottom baryon masses

I discuss several recent highly accurate theoretical predictions for masses of baryons containing the b quark, as well as an effective supersymmetry between heavy quark baryons and mesons. I also suggest some possibilities for observing exotic hadrons containing heavy quarks.

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arXiv2008

The Quark Model and $b$ Baryons

The recent observation at the Tevatron of $Σ_b^{\pm}$ ($uub$ and $ddb$) baryons within 2 MeV of the predicted $Σ_b - Λ_b$ splitting and of $Ξ_b^-$ $(dsb)$ baryons at the Tevatron within a few MeV of predictions has provided strong confirmation for a theoretical approach based on modeling the color hyperfine interaction. The prediction of $M(Ξ^-_b) = 5790$ to 5800 MeV is reviewed and similar methods used to predict the masses of the excited states $Ξ_b^\prime$ and $Ξ_b^*$. The main source of uncertainty is the method used to estimate the mass difference $m_b - m_c$ from known hadrons. We verify that corrections due to the details of the interquark potential and to $Ξ_b$--$Ξ_b^\prime$ mixing are small. For S-wave $qqb$ states we predict $M(Ω_b) = 6052.1 \pm 5.6$ MeV, $M(Ω^*_b) = 6082.8 \pm 5.6$ MeV, and $M(Ξ_b^0) = 5786.7 \pm 3.0$ MeV. For states with one unit of orbital angular momentum between the $b$ quark and the two light quarks we predict $M(Λ_{b[1/2]}) = 5929 \pm 2$ MeV, $M(Λ_{b[3/2]}) = 5940 \pm 2$ MeV, $M(Ξ_{b[1/2]}) = 6106 \pm 4$ MeV, and $M(Ξ_{b[3/2]}) = 6115 \pm 4$ MeV. Results are compared with those of other recent approaches.

hep-ph↗

arXiv2008

Possibility of Exotic States in the Upsilon system

Recent data from Belle show unusually large partial widths Upsilon(5S) --> Upsilon(1S) pi^+pi^- and Υ(5S) --> Υ(2S) pi^+ pi^-. The Z(4430) narrow resonance also reported by Belle in psi' pi^+ spectrum has the properties expected of a (cbar c u dbar) charged isovector tetraquark T^{+-}_cc The analogous state T^{+-} in the bottom sector might mediate anomalously large cascade decays in the Upsilon system, Upsilon(mS) --> T^{+-}_bb pi^{-+} --> Upsilon(nS) pi^+ π^-, with a tetraquark-pion intermediate state. We suggest looking for the (bbar b u dbar) tetraquark in these decays as peaks in the invariant mass of Upsilon(1S) pi or Upsilon(2S) pi systems. The (bbar b u sbar) tetraquark can appear in the observed decays Upsilon(5S) --> Upsilon(1S) K^+ K^- as a peak in the invariant mass of Upsilon(1S) K system. We review the model showing that these tetraquarks are below the two heavy meson threshold, but respectively above the Upsilon pi pi and Upsilon K Kbar thresholds.

hep-ph↗

arXiv2008

Spontaneous Breaking of Rotational Symmetry in Rotating Solitons - a Toy Model of Excited Nucleons with High Angular Momentum

We study the phenomenon of spontaneous breaking of rotational symmetry (SBRS) in the rotating solutions of two types of baby Skyrme models. In the first the domain is a two-sphere and in the other, the Skyrmions are confined to the interior of a unit disk. Numerical full-field results show that when the angular momentum of the Skyrmions increases above a certain critical value, the rotational symmetry of the solutions is broken and the minimal energy configurations become less symmetric. We propose a possible mechanism as to why SBRS is present in the rotating solutions of these models, while it is not observed in the `usual' baby Skyrme model. Our results might be relevant for a qualitative understanding of the non-spherical deformation of excited nucleons with high orbital angular momentum.

hep-ph↗

arXiv2008

Hexagonal Structure of Baby Skyrmion Lattices

We study the zero-temperature crystalline structure of baby Skyrmions by applying a full-field numerical minimization algorithm to baby Skyrmions placed inside different parallelogramic unit-cells and imposing periodic boundary conditions. We find that within this setup, the minimal energy is obtained for the hexagonal lattice, and that in the resulting configuration the Skyrmion splits into quarter-Skyrmions. In particular, we find that the energy in the hexagonal case is lower than the one obtained on the well-studied rectangular lattice, in which splitting into half-Skyrmions is observed.

hep-th↗

arXiv2007

Baby Skyrmions on the Two-Sphere

We find the static multi-soliton solutions of the baby Skyrme model on the two-sphere for topological charges 1 =< B =< 14. Numerical full-field results show that the charge-one Skyrmion is spherical, the charge-two Skyrmion is toroidal, and Skyrmions with higher charge all have point symmetries which are subgroups of O(3). We find that a rational map ansatz yields very good approximations to the full-field solutions. We point out a strong connection between the discrete symmetries of our solutions and those of corresponding solutions of the 3D Skyrme model.

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arXiv2007

Possibility of Narrow High-Mass Exotic States

Narrow high-mass states can arise despite large phase space when two nearly degenerate states are coupled to the same dominant decay mode. Mixing via a final-state interaction loop diagram can produce one very broad state and one narrow state. Such a situation is generic in exotic hadrons where a color singlet with given flavor and spin quantum numbers can be constructed with two distinct internal color couplings of quarks. The simplest realization of this idea are the (Q Qbar q qbar) tetraquarks containing two heavy and two light quarks. We discuss possible experimental implications, including recent data from Belle.

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arXiv2007

Rotational symmetry breaking in baby Skyrme models

We consider multisolitons with charges 1 =< B =< 5 in the baby Skyrme model for the one-parametric family of potentials U=μ^2 (1-ϕ_3)^s with 0<s =< 4. This class of potentials is a generalization of the `old' (s=1) and `holomorphic' (s=4) baby Skyrme models. We find that for charge one, stable solutions exist for every value of s and they are rotationally-symmetric. For higher charges, stable solutions exist only below s \approx 2. In the charge-two sector the stable solutions are always rotationally-symmetric and ring-like. For charge three and above, rotational symmetry is exhibited only in the small s region; above a certain critical value of s, this symmetry is broken and a strong repulsion between the constituent one-Skyrmions becomes apparent. We also compute the spatial energy distributions of these solutions.

hep-th↗

arXiv2007

The New Sigma_b multiplet, heavy baryon mass predictions, meson-baryon universality and magnetic moments of Lambda_c and Lambda_b

The recent measurement by CDF M(Sigma_b)-M(Lambda_b)=192 MeV is in striking agreement with our theoretical prediction M(Sigma_b)-M(Lambda_b) = 194 MeV. In addition, the measured splitting M(Sigma_b*)-M(Sigma_b) = 21 MeV agrees well with the predicted splitting of 22 MeV. We point out the connection between these predictions and an effective supersymmetry between mesons and baryons related by replacing a light antiquark by a light diquark. We discuss the theoretical framework behind these predictions and use it to provide additional predictions for the masses of spin-1/2 and spin-3/2 baryons containing heavy quarks, as well as magnetic moments of Lambda_b and Lambda_c.

hep-ph↗

arXiv2007

Predictions for masses of bottom baryons

The recent observation of Sigma_b^{+-} (uub and ddb) and Xi_b^- (dsb) baryons at the Tevatron within 2 MeV of our theoretical predictions provides a strong motivation for applying the same theoretical approach, based on modeling the color hyperfine interaction, to predict the masses of other bottom baryons which might be observed in the foreseeable future. For S-wave qqb states we predict M(Omega_b) = 6052.1+-5.6 MeV, M(Omega^*_b) = 6082.8+-5.6 MeV, and M(Xi_b^0) = 5786.7 +- 3.0 MeV. For states with one unit of orbital angular momentum between the b quark and the two light quarks we predict M(Lambda_{b[1/2]}) = 5929+-2 MeV, M(Lambda_{b[3/2]}) = 5940+-2 MeV, M(Xi_{b[1/2]}) = 6106+-4 MeV, and M(Xi_{b[3/2]}) = 6115+-4 MeV.

hep-ph↗

arXiv2007

Predictions for masses of Xi_b baryons

The recent observation by CDF of Sigma_b^{+-} (uub and ddb) baryons within 2 MeV of the predicted Sigma_b - Lambda_b splitting has provided strong confirmation for the theoretical approach based on modeling the color hyperfine interaction. We now apply this approach to predict the masses of the Xi_b family of baryons with quark content usb and dsb - the ground state Xi_b at 5790 to 5800 MeV, and the excited states Xi_b^' and Xi_b^*. The main source of uncertainty is the method used to estimate the mass difference m_b - m_c from known hadrons. We verify that corrections due to the details of the interquark potential and to Xi_b-Xi_b^' mixing are small.

hep-ph↗