The Experts below are selected from a list of 318 Experts worldwide ranked by ideXlab platform
Howard Baer - One of the best experts on this subject based on the ideXlab platform.
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thermal leptogenesis and the gravitino problem in the asaka yanagida axion axino dark matter scenario
Journal of Cosmology and Astroparticle Physics, 2011Co-Authors: Howard Baer, S Kraml, Andre Lessa, S SekmenAbstract:A successful implementation of thermal leptogenesis requires the re-heat temperature after inflation TR to exceed ~ 2 × 109 GeV. Such a high TR value typically leads to an overproduction of Gravitinos in the early universe, which will cause conflicts, mainly with BBN constraints. Asaka and Yanagida (AY) have proposed that these two issues can be reconciled in the context of the Peccei-Quinn augmented MSSM (PQMSSM) if one adopts a mass hierarchy m(sparticle) > m(gravitino)>m(axino), with m(axino) ~ keV. In this case, sparticle decays bypass the gravitino, and decay more quickly to the axino LSP, thus avoiding the BBN constraints. In addition, thermally produced Gravitinos decay inertly to axion+axino, also avoiding BBN constraints. We calculate the relic abundance of mixed axion/axino dark matter in the AY scenario, and investigate under what conditions a value of TR sufficient for thermal leptogenesis can be generated. A high value of PQ breaking scale fa is needed to suppress overproduction of axinos, while a small vacuum misalignment angle θi is needed to suppress overproduction of axions. The large value of fa results in late decaying neutralinos. We show that, to avoid BBN constraints, the AY scenario requires a rather low thermal abundance of neutralinos, while higher values of neutralino mass also help. We combine these constraint calculations along with entropy production from late decaying saxions, and find the saxion needs to be typically at least several times heavier than the gravitino. A successful implementation of the AY scenario suggests that LHC should discover a spectrum of SUSY particles consistent with weak scale supergravity; that the apparent neutralino abundance is low; that an axion direct detection signal (probably with ma in the sub-μeV range) may be possible, but no direct or indirect signals for WIMP dark matter should be observed.
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thermal leptogenesis and the gravitino problem in the asaka yanagida axion axino dark matter scenario
arXiv: High Energy Physics - Phenomenology, 2010Co-Authors: Howard Baer, S Kraml, Andre Lessa, S SekmenAbstract:A successful implementation of thermal leptogenesis requires the re-heat temperature after inflation T_R to exceed ~2\times 10^9 GeV. Such a high T_R value typically leads to an overproduction of Gravitinos in the early universe, which will cause conflicts, mainly with BBN constraints. Asaka and Yanagida (AY) have proposed that these two issues can be reconciled in the context of the Peccei-Quinn augmented MSSM (PQMSSM) if one adopts a mass hierarchy m(sparticle)>m(gravitino)>m(axino), with m(axino) keV. We calculate the relic abundance of mixed axion/axino dark matter in the AY scenario, and investigate under what conditions a value of T_R sufficient for thermal leptogenesis can be generated. A high value of PQ breaking scale f_a is needed to suppress overproduction of axinos, while a small vacuum misalignment angle \theta_i is needed to suppress overproduction of axions. The large value of f_a results in late decaying neutralinos. To avoid BBN constraints, the AY scenario requires a low thermal abundance of neutralinos and high values of neutralino mass. We include entropy production from late decaying saxions, and find the saxion needs to be typically at least several times heavier than the gravitino. A viable AY scenario suggests that LHC should discover a spectrum of SUSY particles consistent with weak scale supergravity; that the apparent neutralino abundance is low; that a possible axion detection signal (probably with m_axion in the sub-micro-eV range) should occur, but no direct or indirect signals for WIMP dark matter should be observed.
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reconciling thermal leptogenesis with the gravitino problem in susy models with mixed axion axino dark matter
Journal of Cosmology and Astroparticle Physics, 2010Co-Authors: Howard Baer, S Kraml, Andre Lessa, S SekmenAbstract:Successful implementation of thermal leptogenesis requires re-heat temperatures T{sub R}∼>2 × 10{sup 9} GeV, in apparent conflict with SUSY models with TeV-scale Gravitinos, which require much lower T{sub R} in order to avoid Big Bang Nucleosynthesis (BBN) constraints. We show that mixed axion/axino dark matter can reconcile thermal leptogenesis with the gravitino problem in models with m{sub G-tilde}∼>30 TeV, a rather high Peccei-Quinn breaking scale and an initial mis-alignment angle θ{sub i} < 1. We calculate axion and axino dark matter production from four sources, and impose BBN constraints on long-lived Gravitinos and neutralinos. Moreover, we discuss several SUSY models which naturally have gravitino masses of the order of tens of TeV. We find a reconciliation difficult in Yukawa-unified SUSY and in AMSB with a wino-like lightest neutralino. However, T{sub R} ∼ 10{sup 10}−10{sup 12} GeV can easily be achieved in effective SUSY and in models based on mixed moduli-anomaly mediation. Consequences of this scenario include: 1. an LHC SUSY discovery should be consistent with SUSY models with a large gravitino mass, 2. an apparent neutralino relic abundance Ω{sub Z-tilde} {sub 1}h{sup 2}∼<1, 3. no WIMP direct or indirect detection signals should be found, and 4. the axion mass shouldmore » be less than ∼ 10{sup −6} eV, somewhat below the conventional range which is explored by microwave cavity axion detection experiments.« less
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reconciling thermal leptogenesis with the gravitino problem in susy models with mixed axion axino dark matter
arXiv: High Energy Physics - Phenomenology, 2010Co-Authors: Howard Baer, S Kraml, Andre Lessa, S SekmenAbstract:Successful implementation of thermal leptogenesis requires re-heat temperatures T_R\agt 2\times 10^9 GeV, in apparent conflict with SUSY models with TeV-scale Gravitinos, which require much lower T_R in order to avoid Big Bang Nucleosynthesis (BBN) constraints. We show that mixed axion/axino dark matter can reconcile thermal leptogenesis with the gravitino problem in models with m_{\tG}\agt 30 TeV, a rather high Peccei-Quinn breaking scale and an initial mis-alignment angle \theta_i < 1. We calculate axion and axino dark matter production from four sources, and impose BBN constraints on long-lived Gravitinos and neutralinos. Moreover, we discuss several SUSY models which naturally have gravitino masses of the order of tens of TeV. We find a reconciliation difficult in Yukawa-unified SUSY and in AMSB with a wino-like lightest neutralino. However, T_R\sim 10^{10}-10^{12} GeV can easily be achieved in effective SUSY and in models based on mixed moduli-anomaly mediation. Consequences of this scenario include: 1. an LHC SUSY discovery should be consistent with SUSY models with a large gravitino mass, 2. an apparent neutralino relic abundance \Omega_{\tz_1}h^2\alt 1, 3. no WIMP direct or indirect detection signals should be found, and 4. the axion mass should be less than \sim 10^{-6} eV, somewhat below the conventional range which is explored by microwave cavity axion detection experiments.
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so 10 susy guts the gravitino problem non thermal leptogenesis and axino dark matter
Physics Letters B, 2008Co-Authors: Howard Baer, Heaya SummyAbstract:Abstract Simple SUSY GUT models based on the gauge group SO ( 10 ) require t – b – τ Yukawa coupling unification, in addition to gauge coupling and matter unification. The Yukawa coupling unification places strong constraints on the expected superparticle mass spectrum, with scalar masses ∼ 10 TeV while gaugino masses are quite light. A problem generic to all supergravity models comes from overproduction of Gravitinos in the early universe: if Gravitinos are unstable, then their late decays may destroy the predictions of Big Bang nucleosynthesis. We present a Yukawa-unified SO ( 10 ) SUSY GUT scenario which avoids the gravitino problem, gives rise to the correct matter–antimatter asymmetry via non-thermal leptogenesis, and is consistent with the WMAP-measured abundance of cold dark matter due to the presence of an axino LSP. To maintain a consistent cosmology for Yukawa-unified SUSY models, we require a re-heat temperature T R ∼ 10 6 – 10 7 GeV , an axino mass around ∼ 0.1 – 10 MeV , and a PQ breaking scale f a ∼ 10 12 GeV .
S Sekmen - One of the best experts on this subject based on the ideXlab platform.
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thermal leptogenesis and the gravitino problem in the asaka yanagida axion axino dark matter scenario
Journal of Cosmology and Astroparticle Physics, 2011Co-Authors: Howard Baer, S Kraml, Andre Lessa, S SekmenAbstract:A successful implementation of thermal leptogenesis requires the re-heat temperature after inflation TR to exceed ~ 2 × 109 GeV. Such a high TR value typically leads to an overproduction of Gravitinos in the early universe, which will cause conflicts, mainly with BBN constraints. Asaka and Yanagida (AY) have proposed that these two issues can be reconciled in the context of the Peccei-Quinn augmented MSSM (PQMSSM) if one adopts a mass hierarchy m(sparticle) > m(gravitino)>m(axino), with m(axino) ~ keV. In this case, sparticle decays bypass the gravitino, and decay more quickly to the axino LSP, thus avoiding the BBN constraints. In addition, thermally produced Gravitinos decay inertly to axion+axino, also avoiding BBN constraints. We calculate the relic abundance of mixed axion/axino dark matter in the AY scenario, and investigate under what conditions a value of TR sufficient for thermal leptogenesis can be generated. A high value of PQ breaking scale fa is needed to suppress overproduction of axinos, while a small vacuum misalignment angle θi is needed to suppress overproduction of axions. The large value of fa results in late decaying neutralinos. We show that, to avoid BBN constraints, the AY scenario requires a rather low thermal abundance of neutralinos, while higher values of neutralino mass also help. We combine these constraint calculations along with entropy production from late decaying saxions, and find the saxion needs to be typically at least several times heavier than the gravitino. A successful implementation of the AY scenario suggests that LHC should discover a spectrum of SUSY particles consistent with weak scale supergravity; that the apparent neutralino abundance is low; that an axion direct detection signal (probably with ma in the sub-μeV range) may be possible, but no direct or indirect signals for WIMP dark matter should be observed.
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thermal leptogenesis and the gravitino problem in the asaka yanagida axion axino dark matter scenario
arXiv: High Energy Physics - Phenomenology, 2010Co-Authors: Howard Baer, S Kraml, Andre Lessa, S SekmenAbstract:A successful implementation of thermal leptogenesis requires the re-heat temperature after inflation T_R to exceed ~2\times 10^9 GeV. Such a high T_R value typically leads to an overproduction of Gravitinos in the early universe, which will cause conflicts, mainly with BBN constraints. Asaka and Yanagida (AY) have proposed that these two issues can be reconciled in the context of the Peccei-Quinn augmented MSSM (PQMSSM) if one adopts a mass hierarchy m(sparticle)>m(gravitino)>m(axino), with m(axino) keV. We calculate the relic abundance of mixed axion/axino dark matter in the AY scenario, and investigate under what conditions a value of T_R sufficient for thermal leptogenesis can be generated. A high value of PQ breaking scale f_a is needed to suppress overproduction of axinos, while a small vacuum misalignment angle \theta_i is needed to suppress overproduction of axions. The large value of f_a results in late decaying neutralinos. To avoid BBN constraints, the AY scenario requires a low thermal abundance of neutralinos and high values of neutralino mass. We include entropy production from late decaying saxions, and find the saxion needs to be typically at least several times heavier than the gravitino. A viable AY scenario suggests that LHC should discover a spectrum of SUSY particles consistent with weak scale supergravity; that the apparent neutralino abundance is low; that a possible axion detection signal (probably with m_axion in the sub-micro-eV range) should occur, but no direct or indirect signals for WIMP dark matter should be observed.
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reconciling thermal leptogenesis with the gravitino problem in susy models with mixed axion axino dark matter
Journal of Cosmology and Astroparticle Physics, 2010Co-Authors: Howard Baer, S Kraml, Andre Lessa, S SekmenAbstract:Successful implementation of thermal leptogenesis requires re-heat temperatures T{sub R}∼>2 × 10{sup 9} GeV, in apparent conflict with SUSY models with TeV-scale Gravitinos, which require much lower T{sub R} in order to avoid Big Bang Nucleosynthesis (BBN) constraints. We show that mixed axion/axino dark matter can reconcile thermal leptogenesis with the gravitino problem in models with m{sub G-tilde}∼>30 TeV, a rather high Peccei-Quinn breaking scale and an initial mis-alignment angle θ{sub i} < 1. We calculate axion and axino dark matter production from four sources, and impose BBN constraints on long-lived Gravitinos and neutralinos. Moreover, we discuss several SUSY models which naturally have gravitino masses of the order of tens of TeV. We find a reconciliation difficult in Yukawa-unified SUSY and in AMSB with a wino-like lightest neutralino. However, T{sub R} ∼ 10{sup 10}−10{sup 12} GeV can easily be achieved in effective SUSY and in models based on mixed moduli-anomaly mediation. Consequences of this scenario include: 1. an LHC SUSY discovery should be consistent with SUSY models with a large gravitino mass, 2. an apparent neutralino relic abundance Ω{sub Z-tilde} {sub 1}h{sup 2}∼<1, 3. no WIMP direct or indirect detection signals should be found, and 4. the axion mass shouldmore » be less than ∼ 10{sup −6} eV, somewhat below the conventional range which is explored by microwave cavity axion detection experiments.« less
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reconciling thermal leptogenesis with the gravitino problem in susy models with mixed axion axino dark matter
arXiv: High Energy Physics - Phenomenology, 2010Co-Authors: Howard Baer, S Kraml, Andre Lessa, S SekmenAbstract:Successful implementation of thermal leptogenesis requires re-heat temperatures T_R\agt 2\times 10^9 GeV, in apparent conflict with SUSY models with TeV-scale Gravitinos, which require much lower T_R in order to avoid Big Bang Nucleosynthesis (BBN) constraints. We show that mixed axion/axino dark matter can reconcile thermal leptogenesis with the gravitino problem in models with m_{\tG}\agt 30 TeV, a rather high Peccei-Quinn breaking scale and an initial mis-alignment angle \theta_i < 1. We calculate axion and axino dark matter production from four sources, and impose BBN constraints on long-lived Gravitinos and neutralinos. Moreover, we discuss several SUSY models which naturally have gravitino masses of the order of tens of TeV. We find a reconciliation difficult in Yukawa-unified SUSY and in AMSB with a wino-like lightest neutralino. However, T_R\sim 10^{10}-10^{12} GeV can easily be achieved in effective SUSY and in models based on mixed moduli-anomaly mediation. Consequences of this scenario include: 1. an LHC SUSY discovery should be consistent with SUSY models with a large gravitino mass, 2. an apparent neutralino relic abundance \Omega_{\tz_1}h^2\alt 1, 3. no WIMP direct or indirect detection signals should be found, and 4. the axion mass should be less than \sim 10^{-6} eV, somewhat below the conventional range which is explored by microwave cavity axion detection experiments.
S Kraml - One of the best experts on this subject based on the ideXlab platform.
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thermal leptogenesis and the gravitino problem in the asaka yanagida axion axino dark matter scenario
Journal of Cosmology and Astroparticle Physics, 2011Co-Authors: Howard Baer, S Kraml, Andre Lessa, S SekmenAbstract:A successful implementation of thermal leptogenesis requires the re-heat temperature after inflation TR to exceed ~ 2 × 109 GeV. Such a high TR value typically leads to an overproduction of Gravitinos in the early universe, which will cause conflicts, mainly with BBN constraints. Asaka and Yanagida (AY) have proposed that these two issues can be reconciled in the context of the Peccei-Quinn augmented MSSM (PQMSSM) if one adopts a mass hierarchy m(sparticle) > m(gravitino)>m(axino), with m(axino) ~ keV. In this case, sparticle decays bypass the gravitino, and decay more quickly to the axino LSP, thus avoiding the BBN constraints. In addition, thermally produced Gravitinos decay inertly to axion+axino, also avoiding BBN constraints. We calculate the relic abundance of mixed axion/axino dark matter in the AY scenario, and investigate under what conditions a value of TR sufficient for thermal leptogenesis can be generated. A high value of PQ breaking scale fa is needed to suppress overproduction of axinos, while a small vacuum misalignment angle θi is needed to suppress overproduction of axions. The large value of fa results in late decaying neutralinos. We show that, to avoid BBN constraints, the AY scenario requires a rather low thermal abundance of neutralinos, while higher values of neutralino mass also help. We combine these constraint calculations along with entropy production from late decaying saxions, and find the saxion needs to be typically at least several times heavier than the gravitino. A successful implementation of the AY scenario suggests that LHC should discover a spectrum of SUSY particles consistent with weak scale supergravity; that the apparent neutralino abundance is low; that an axion direct detection signal (probably with ma in the sub-μeV range) may be possible, but no direct or indirect signals for WIMP dark matter should be observed.
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thermal leptogenesis and the gravitino problem in the asaka yanagida axion axino dark matter scenario
arXiv: High Energy Physics - Phenomenology, 2010Co-Authors: Howard Baer, S Kraml, Andre Lessa, S SekmenAbstract:A successful implementation of thermal leptogenesis requires the re-heat temperature after inflation T_R to exceed ~2\times 10^9 GeV. Such a high T_R value typically leads to an overproduction of Gravitinos in the early universe, which will cause conflicts, mainly with BBN constraints. Asaka and Yanagida (AY) have proposed that these two issues can be reconciled in the context of the Peccei-Quinn augmented MSSM (PQMSSM) if one adopts a mass hierarchy m(sparticle)>m(gravitino)>m(axino), with m(axino) keV. We calculate the relic abundance of mixed axion/axino dark matter in the AY scenario, and investigate under what conditions a value of T_R sufficient for thermal leptogenesis can be generated. A high value of PQ breaking scale f_a is needed to suppress overproduction of axinos, while a small vacuum misalignment angle \theta_i is needed to suppress overproduction of axions. The large value of f_a results in late decaying neutralinos. To avoid BBN constraints, the AY scenario requires a low thermal abundance of neutralinos and high values of neutralino mass. We include entropy production from late decaying saxions, and find the saxion needs to be typically at least several times heavier than the gravitino. A viable AY scenario suggests that LHC should discover a spectrum of SUSY particles consistent with weak scale supergravity; that the apparent neutralino abundance is low; that a possible axion detection signal (probably with m_axion in the sub-micro-eV range) should occur, but no direct or indirect signals for WIMP dark matter should be observed.
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reconciling thermal leptogenesis with the gravitino problem in susy models with mixed axion axino dark matter
Journal of Cosmology and Astroparticle Physics, 2010Co-Authors: Howard Baer, S Kraml, Andre Lessa, S SekmenAbstract:Successful implementation of thermal leptogenesis requires re-heat temperatures T{sub R}∼>2 × 10{sup 9} GeV, in apparent conflict with SUSY models with TeV-scale Gravitinos, which require much lower T{sub R} in order to avoid Big Bang Nucleosynthesis (BBN) constraints. We show that mixed axion/axino dark matter can reconcile thermal leptogenesis with the gravitino problem in models with m{sub G-tilde}∼>30 TeV, a rather high Peccei-Quinn breaking scale and an initial mis-alignment angle θ{sub i} < 1. We calculate axion and axino dark matter production from four sources, and impose BBN constraints on long-lived Gravitinos and neutralinos. Moreover, we discuss several SUSY models which naturally have gravitino masses of the order of tens of TeV. We find a reconciliation difficult in Yukawa-unified SUSY and in AMSB with a wino-like lightest neutralino. However, T{sub R} ∼ 10{sup 10}−10{sup 12} GeV can easily be achieved in effective SUSY and in models based on mixed moduli-anomaly mediation. Consequences of this scenario include: 1. an LHC SUSY discovery should be consistent with SUSY models with a large gravitino mass, 2. an apparent neutralino relic abundance Ω{sub Z-tilde} {sub 1}h{sup 2}∼<1, 3. no WIMP direct or indirect detection signals should be found, and 4. the axion mass shouldmore » be less than ∼ 10{sup −6} eV, somewhat below the conventional range which is explored by microwave cavity axion detection experiments.« less
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reconciling thermal leptogenesis with the gravitino problem in susy models with mixed axion axino dark matter
arXiv: High Energy Physics - Phenomenology, 2010Co-Authors: Howard Baer, S Kraml, Andre Lessa, S SekmenAbstract:Successful implementation of thermal leptogenesis requires re-heat temperatures T_R\agt 2\times 10^9 GeV, in apparent conflict with SUSY models with TeV-scale Gravitinos, which require much lower T_R in order to avoid Big Bang Nucleosynthesis (BBN) constraints. We show that mixed axion/axino dark matter can reconcile thermal leptogenesis with the gravitino problem in models with m_{\tG}\agt 30 TeV, a rather high Peccei-Quinn breaking scale and an initial mis-alignment angle \theta_i < 1. We calculate axion and axino dark matter production from four sources, and impose BBN constraints on long-lived Gravitinos and neutralinos. Moreover, we discuss several SUSY models which naturally have gravitino masses of the order of tens of TeV. We find a reconciliation difficult in Yukawa-unified SUSY and in AMSB with a wino-like lightest neutralino. However, T_R\sim 10^{10}-10^{12} GeV can easily be achieved in effective SUSY and in models based on mixed moduli-anomaly mediation. Consequences of this scenario include: 1. an LHC SUSY discovery should be consistent with SUSY models with a large gravitino mass, 2. an apparent neutralino relic abundance \Omega_{\tz_1}h^2\alt 1, 3. no WIMP direct or indirect detection signals should be found, and 4. the axion mass should be less than \sim 10^{-6} eV, somewhat below the conventional range which is explored by microwave cavity axion detection experiments.
Andre Lessa - One of the best experts on this subject based on the ideXlab platform.
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thermal leptogenesis and the gravitino problem in the asaka yanagida axion axino dark matter scenario
Journal of Cosmology and Astroparticle Physics, 2011Co-Authors: Howard Baer, S Kraml, Andre Lessa, S SekmenAbstract:A successful implementation of thermal leptogenesis requires the re-heat temperature after inflation TR to exceed ~ 2 × 109 GeV. Such a high TR value typically leads to an overproduction of Gravitinos in the early universe, which will cause conflicts, mainly with BBN constraints. Asaka and Yanagida (AY) have proposed that these two issues can be reconciled in the context of the Peccei-Quinn augmented MSSM (PQMSSM) if one adopts a mass hierarchy m(sparticle) > m(gravitino)>m(axino), with m(axino) ~ keV. In this case, sparticle decays bypass the gravitino, and decay more quickly to the axino LSP, thus avoiding the BBN constraints. In addition, thermally produced Gravitinos decay inertly to axion+axino, also avoiding BBN constraints. We calculate the relic abundance of mixed axion/axino dark matter in the AY scenario, and investigate under what conditions a value of TR sufficient for thermal leptogenesis can be generated. A high value of PQ breaking scale fa is needed to suppress overproduction of axinos, while a small vacuum misalignment angle θi is needed to suppress overproduction of axions. The large value of fa results in late decaying neutralinos. We show that, to avoid BBN constraints, the AY scenario requires a rather low thermal abundance of neutralinos, while higher values of neutralino mass also help. We combine these constraint calculations along with entropy production from late decaying saxions, and find the saxion needs to be typically at least several times heavier than the gravitino. A successful implementation of the AY scenario suggests that LHC should discover a spectrum of SUSY particles consistent with weak scale supergravity; that the apparent neutralino abundance is low; that an axion direct detection signal (probably with ma in the sub-μeV range) may be possible, but no direct or indirect signals for WIMP dark matter should be observed.
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thermal leptogenesis and the gravitino problem in the asaka yanagida axion axino dark matter scenario
arXiv: High Energy Physics - Phenomenology, 2010Co-Authors: Howard Baer, S Kraml, Andre Lessa, S SekmenAbstract:A successful implementation of thermal leptogenesis requires the re-heat temperature after inflation T_R to exceed ~2\times 10^9 GeV. Such a high T_R value typically leads to an overproduction of Gravitinos in the early universe, which will cause conflicts, mainly with BBN constraints. Asaka and Yanagida (AY) have proposed that these two issues can be reconciled in the context of the Peccei-Quinn augmented MSSM (PQMSSM) if one adopts a mass hierarchy m(sparticle)>m(gravitino)>m(axino), with m(axino) keV. We calculate the relic abundance of mixed axion/axino dark matter in the AY scenario, and investigate under what conditions a value of T_R sufficient for thermal leptogenesis can be generated. A high value of PQ breaking scale f_a is needed to suppress overproduction of axinos, while a small vacuum misalignment angle \theta_i is needed to suppress overproduction of axions. The large value of f_a results in late decaying neutralinos. To avoid BBN constraints, the AY scenario requires a low thermal abundance of neutralinos and high values of neutralino mass. We include entropy production from late decaying saxions, and find the saxion needs to be typically at least several times heavier than the gravitino. A viable AY scenario suggests that LHC should discover a spectrum of SUSY particles consistent with weak scale supergravity; that the apparent neutralino abundance is low; that a possible axion detection signal (probably with m_axion in the sub-micro-eV range) should occur, but no direct or indirect signals for WIMP dark matter should be observed.
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reconciling thermal leptogenesis with the gravitino problem in susy models with mixed axion axino dark matter
Journal of Cosmology and Astroparticle Physics, 2010Co-Authors: Howard Baer, S Kraml, Andre Lessa, S SekmenAbstract:Successful implementation of thermal leptogenesis requires re-heat temperatures T{sub R}∼>2 × 10{sup 9} GeV, in apparent conflict with SUSY models with TeV-scale Gravitinos, which require much lower T{sub R} in order to avoid Big Bang Nucleosynthesis (BBN) constraints. We show that mixed axion/axino dark matter can reconcile thermal leptogenesis with the gravitino problem in models with m{sub G-tilde}∼>30 TeV, a rather high Peccei-Quinn breaking scale and an initial mis-alignment angle θ{sub i} < 1. We calculate axion and axino dark matter production from four sources, and impose BBN constraints on long-lived Gravitinos and neutralinos. Moreover, we discuss several SUSY models which naturally have gravitino masses of the order of tens of TeV. We find a reconciliation difficult in Yukawa-unified SUSY and in AMSB with a wino-like lightest neutralino. However, T{sub R} ∼ 10{sup 10}−10{sup 12} GeV can easily be achieved in effective SUSY and in models based on mixed moduli-anomaly mediation. Consequences of this scenario include: 1. an LHC SUSY discovery should be consistent with SUSY models with a large gravitino mass, 2. an apparent neutralino relic abundance Ω{sub Z-tilde} {sub 1}h{sup 2}∼<1, 3. no WIMP direct or indirect detection signals should be found, and 4. the axion mass shouldmore » be less than ∼ 10{sup −6} eV, somewhat below the conventional range which is explored by microwave cavity axion detection experiments.« less
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reconciling thermal leptogenesis with the gravitino problem in susy models with mixed axion axino dark matter
arXiv: High Energy Physics - Phenomenology, 2010Co-Authors: Howard Baer, S Kraml, Andre Lessa, S SekmenAbstract:Successful implementation of thermal leptogenesis requires re-heat temperatures T_R\agt 2\times 10^9 GeV, in apparent conflict with SUSY models with TeV-scale Gravitinos, which require much lower T_R in order to avoid Big Bang Nucleosynthesis (BBN) constraints. We show that mixed axion/axino dark matter can reconcile thermal leptogenesis with the gravitino problem in models with m_{\tG}\agt 30 TeV, a rather high Peccei-Quinn breaking scale and an initial mis-alignment angle \theta_i < 1. We calculate axion and axino dark matter production from four sources, and impose BBN constraints on long-lived Gravitinos and neutralinos. Moreover, we discuss several SUSY models which naturally have gravitino masses of the order of tens of TeV. We find a reconciliation difficult in Yukawa-unified SUSY and in AMSB with a wino-like lightest neutralino. However, T_R\sim 10^{10}-10^{12} GeV can easily be achieved in effective SUSY and in models based on mixed moduli-anomaly mediation. Consequences of this scenario include: 1. an LHC SUSY discovery should be consistent with SUSY models with a large gravitino mass, 2. an apparent neutralino relic abundance \Omega_{\tz_1}h^2\alt 1, 3. no WIMP direct or indirect detection signals should be found, and 4. the axion mass should be less than \sim 10^{-6} eV, somewhat below the conventional range which is explored by microwave cavity axion detection experiments.
Ruijun Wu - One of the best experts on this subject based on the ideXlab platform.
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partial regularity for a nonlinear sigma model with gravitino in higher dimensions
Calculus of Variations and Partial Differential Equations, 2018Co-Authors: Jurgen Jost, Ruijun WuAbstract:We study the regularity problem of the nonlinear sigma model with gravitino fields in higher dimensions. After setting up the geometric model, we derive the Euler–Lagrange equations and consider the regularity of weak solutions defined in suitable Sobolev spaces. We show that any weak solution is actually smooth under some smallness assumption for certain Morrey norms. By assuming some higher integrability of the vector spinor, we can show a partial regularity result for stationary solutions, provided the gravitino is critical, which means that the corresponding supercurrent vanishes. Moreover, in dimension $$<6$$ , partial regularity holds for stationary solutions with respect to general gravitino fields.
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partial regularity for a nonlinear sigma model with gravitino in higher dimensions
Calculus of Variations and Partial Differential Equations, 2018Co-Authors: Jurgen Jost, Ruijun WuAbstract:We study the regularity problem of the nonlinear sigma model with gravitino fields in higher dimensions. After setting up the geometric model, we derive the Euler–Lagrange equations and consider the regularity of weak solutions defined in suitable Sobolev spaces. We show that any weak solution is actually smooth under some smallness assumption for certain Morrey norms. By assuming some higher integrability of the vector spinor, we can show a partial regularity result for stationary solutions, provided the gravitino is critical, which means that the corresponding supercurrent vanishes. Moreover, in dimension $$<6$$ , partial regularity holds for stationary solutions with respect to general gravitino fields.
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regularity of solutions of the nonlinear sigma model with gravitino
Communications in Mathematical Physics, 2018Co-Authors: Jurgen Jost, Enno Kesler, Jurgen Tolksdorf, Ruijun WuAbstract:We propose a geometric setup to study analytic aspects of a variant of the super symmetric two-dimensional nonlinear sigma model. This functional extends the functional of Dirac-harmonic maps by gravitino fields. The system of Euler–Lagrange equations of the two-dimensional nonlinear sigma model with gravitino is calculated explicitly. The gravitino terms pose additional analytic difficulties to show smoothness of its weak solutions which are overcome using Riviere’s regularity theory and Riesz potential theory.
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partial regularity for a nonlinear sigma model with gravitino in higher dimensions
arXiv: Differential Geometry, 2017Co-Authors: Jurgen Jost, Ruijun WuAbstract:We study the regularity problem of the nonlinear sigma model with gravitino fields in higher dimensions. After setting up the geometric model, we derive the Euler--Lagrange equations and consider the regularity of weak solutions defined in suitable Sobolev spaces. We show that any weak solution is actually smooth under some smallness assumption for certain Morrey norms. By assuming some higher integrability of the vector spinor, we can show a partial regularity result for stationary solutions, provided the gravitino is critical, which means that the corresponding supercurrent vanishes. Moreover, in dimension less than 6, partial regularity holds for stationary solutions with respect to general gravitino fields.
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coarse regularity of solutions to a nonlinear sigma model with l p gravitino
arXiv: Analysis of PDEs, 2017Co-Authors: Jurgen Jost, Ruijun WuAbstract:The regularity of weak solutions of a two-dimensional nonlinear sigma model with coarse gravitino is shown. Here the gravitino is only assumed to be in $L^p$ for some $p>4$. The precise regularity results depend on the value of $p$.
